Chapter XI: Epilogue: 351 (5)

Humbug and misunderstanding in connection with the electrical relations of living tissues were rife, and it was not till after the period we are now considering that electricity came to take a place in rational Medicine. The change came with E. Du Bois-Reymond (1818-96), who took the matter up scientifically about the middle of the nineteenth century (1843 onwards). He showed that a nervous impulse is accompanied by the passage along the nerve of a change of electrical potential. It should be added that, despite all the work since done upon the nervous system, this is still the only physical accompaniment of a nerve impulse that has been detected.

FIG. 71 is the famous ‘Couronne de tasses’. It consists of a series of vessels containing salt water, in which are steeped plates of alternate silver A and zinc Z. The plates are connected by strips of metal _a_ _a_ _a_. If the first and the last cup be connected by a conductor, a current flows from one to the other.

FIG. 72 is a simple voltaic pile, consisting of alternate disks of silver and zinc, sandwiched between wet strips of leather. The pile is held by glass rods _m_ _m_ _m_. From the lowermost disk a strip of metal passes to a vessel containing salt water. A current will pass from the uppermost disk to the vessel if the two are connected by a conductor.

FIG. 73 is a similar apparatus with two piles connected by a metal plate _c c_, and two vessels _b_ _b_. A current will pass between the two vessels _b_ _b_ if they are joined by a conductor.

]

§ 5. _Discovery of the Nature of the Air._

The seventeenth century saw advances in the knowledge of the air. Boyle (1654, p. 124) had shown by means of his air-pump that air was a material substance and could be weighed. By exhausting the air from a vessel in which an animal had been placed, he showed that it was this material substance and no ether, spirit, or other mysterious entity which supported respiration. Mayow (1668, p. 126) proved that a part only of the air was necessary for life, and later that this same part was removed equally by respiration and combustion (Figs. 74-5). His work was forgotten for a hundred years. The great theorists, Stahl, Boerhaave and Haller, knew him not, and Stahl’s doctrine of _phlogiston_ set back the hands of the clock. No advance was made till the work of Joseph Black (1728-99) which appeared soon after the middle of the eighteenth century.

FIG. 74. A candle is burning and a piece of inflammable material is being ignited in a glass vial by a burning-glass, the mouth of which is under the surface of the water. The air can, if desired, be changed or sampled through the attached tube.

FIG. 75. A mouse confined under a glass cover. The air under this cover communicates with that in the vessel below, and can be cut off more or less completely by means of a more or less porous diaphragm.

]

Black was a cautious investigator and his success was due to the accuracy of his measurements. He was aware of the fact that chalk, when heated, is transformed into quicklime (equation 1, p. 152), thereby losing its power of effervescing with acids, but gaining the power of absorbing water (equation 2). In modern nomenclature, the changes are:

(1) CaCO_{3} = CaO + CO
(2) CaO + HO = Ca(OH)_{2}

The first achievement of Black was to show that in the process of heating the chalk lost weight (equation 1). This was a blow at the phlogiston theory, for it had been supposed that quicklime consisted of chalk _plus_ phlogiston, and that the phlogiston was conveyed to it during the heating. Black now showed that if slaked lime be treated with a mild alkali, such as the carbonate of sodium, it is changed back to the state in which it was before heating, in fact into chalk, while the mild alkali is converted into a caustic alkali. As we now express it:

(3) Ca(OH)_{2} + Na_{2}CO_{3} = CaCO_{3} + 2NaOH

Black’s triumph consisted essentially in showing that reactions (1) and (3) were indefinitely reversible and that the same amount of CaCO_{3} could always be extracted from (3) as was put into (1). Moreover, he showed that a definite amount of chalk, whether heated into quicklime or not, neutralized an equal weight of acid, the only difference being that the neutralization took place with effervescence and loss of weight if the chalk were unheated, and without effervescence or loss of weight if the chalk were first heated into quicklime. Thus:

(4) _Unheated_ CaCO_{3} + 2HCl = CaCl_{2} + H_{2}O + CO_{2}
(5) _Heated_ CaO + 2HCl = CaCl_{2} + H_{2}O

The substance given off by the chalk in (1), absorbed by it in (3), and produced by the reaction (4), he named _fixed air_. We now call it _Carbon dioxide_. The conversion of caustic lime into ordinary chalk by exposure, CaO + CO_{2} = CaCO_{3}, proves that Carbon dioxide is a normal constituent of the atmosphere. Black learned something of its properties, and his work is also of very great importance as the first detailed quantitative study of a chemical reaction and its reversal. The properties of Carbon dioxide were further investigated (1766) by Henry Cavendish (1731-1810).

The next advance in the chemistry of the air was made by the English Unitarian Divine, Joseph Priestley (1733-1804). A series of important observations was made by him in the seventies and eighties of the eighteenth century. He showed that green growing plants would make respired air again respirable, and that they gave off a respirable gas. In 1774 he prepared Oxygen by heating certain oxides, though, still hampered by the phlogiston theory, he failed to recognize the nature of the oxygen he had produced. The conclusions of his striking experiments on blood, which he showed to depend on this same agent for its changes from venous to arterial, were similarly vitiated.

FIG. 76. APPARATUS from Joseph Priestley’s _Experiments and Observations on different Kinds of Air_, Birmingham, 1774. In the background can be seen an experiment on the effect of combustion on confined air. There are also two cylinders inverted over water in which green plants are growing. In one of them the growing plant has given off a gas (oxygen) which Priestley showed could support both combustion and respiration. In the foreground under a bell-jar are some mice on which Priestley performed respiratory experiments.

]

The real passage to the modern point of view in our knowledge of the air was made by the brilliant French chemist Antoine Laurent Lavoisier (1743-94). He made an extensive quantitative investigation of the changes during breathing (Fig. 77), burning, and calcination. In the course of these he discovered the true composition of respired air, and showed how both Carbon dioxide and water are normal products of the act of breathing. If clear grasp of the implication of discovery be made the test, Lavoisier must be regarded as the discoverer of Oxygen.

Cavendish (1731-1810) had already discovered the composition of water (1785). Lavoisier concluded that water and Carbon dioxide are produced by the process of oxidation in the lungs, and that it is this oxidization process, and not any innate quality of a mysterious character in the body or in the blood, that is responsible for the bodily heat. Lavoisier introduced much of the chemical nomenclature that we still employ. So far as respiration is concerned, subsequent research has added much to his standpoint. In the purely chemical aspect, however, it has altered little, though we now know that the tissues and not the lungs are the seat of oxidation.

FIG. 77. LAVOISIER in his laboratory making experiments on breathing. To the right Madame Lavoisier sits at a table, taking notes. Lavoisier stands behind, directing. To the left is the subject of the experiment. His face is covered with a mask provided with a valve. He is breathing into the apparatus. An assistant feels his pulse while a second assistant collects the respired air in a bell-jar inverted over a trough.

From a contemporary sketch.

]

§ 6. _Morbid Anatomy becomes a Science._

The main intellectual movement of the seventeenth and eighteenth centuries had been focused, so far as Medicine was concerned, on the manner of working of the animal body, the department that we now term Physiology. It was necessary to obtain clear concepts of the action of the body in health before venturing into discussion of its action in disease. Towards the end of the seventeenth century, an industrious compiler had put together all the then published records of post-mortem examinations up to his time. During the first part of the eighteenth century many practitioners in Physic and in Surgery published isolated cases or groups of cases connected with particular diseases. Boerhaave regularly attended post-mortem examinations (p. 140). No general pathological principles had, however, yet been elicited on a scientific basis. The theories of disease such as those of Boerhaave were perforce still mainly speculative, for there were no extensive records of the correlation of symptoms during life with the appearances of the organs of the body after death, the subject we now call ‘Morbid Anatomy’. This gap was first effectively bridged by Morgagni.

Giovanni Battista Morgagni (1682-1771) was professor at Padua for no less than fifty-six years. During this time he performed an enormous number of post-mortem examinations, and made important contributions to Descriptive Anatomy. In his seventy-ninth year, eleven years before his death, there emerged from his enormous experience his work _On the sites and causes of disease_. This classical treatise may still be read with profit. Its leading feature is the very careful way in which actual cases are recorded. The life-history of the patient, the history of his disease, the events in connection with his final illness and death, are all recounted with detail and care. The condition of the organs at the post-mortem examination is minutely described and an attempt is made to explain how the symptoms were the result of the lesions. Morgagni is justly said to have introduced the ‘anatomical concept’ into the practice of medicine. This concept is one of the main elements in modern diagnosis, and a modern physician, in reflecting on a case, considers first whether he is able to express the symptoms in terms of lesion. There are many lesions of great importance and frequent occurrence which Morgagni was the first to describe.

The task which Morgagni had undertaken was worthily continued by the Scot, Matthew Baillie (1761-1823), nephew, pupil, and heir of William Hunter (p. 165). Baillie was a successful London practitioner. He followed a new and convenient method in arranging his work according to organs instead of by symptoms, as Morgagni had done. Baillie performed post-mortem examinations on several men of eminence, among them Dr. Johnson, whose lung he describes (see Fig. 78).

The task of naked-eye pathological anatomy, effectively begun by Morgagni, was effectively completed by Karl Rokitansky of Vienna (1804-78). His work (1842-6) was based on an experience extending over 30,000 post-mortems! Though disfigured by a bizarre theory, it left but few gaps for subsequent workers. From now on, the science of Pathology was to be prosecuted in a new spirit and with new instruments. Even in his own day Rokitansky was something of an anachronism, with his pure naked-eye anatomy hardly ever involving experimental evidence on the one hand or the findings of the microscope on the other.

FIG. 78. PART OF THE LUNG OF DR. SAMUEL JOHNSON, from a drawing published by Matthew Baillie. Johnson was a fat, unwieldy man, with a great barrel chest, who suffered for many years from shortness of breath. These are common associations with the pathological condition known as _Emphysema_, in which the lungs, which are normally of fine spongy texture, become full of abnormally large cavities, so that, as Baillie remarks, they come ‘to resemble the air cells of the lungs of amphibious animals’ (cf. Fig. 45, p. 116). In the figure B represents the external part of the lung and A its cut surface. On the cut surface the large cellular structure can be seen. The very dark points are the orifices of cut branches of the pulmonary vessels.

]

§ 7. _Clinical Methods and Instruments._

The great teachers of the earlier eighteenth century, though better equipped as regards knowledge than their predecessors, had hardly any better means of diagnosis. Pulse-measurers and thermometers such as those of Sanctorius and Galileo (p. 109) had proved impracticable by the bedside. The microscope had not yet entered into Clinical Medicine. Chemical analysis as applied to disease had proved, as yet, of little value.

The first efficient instrument of precision to merit clinical adoption was the ‘pulse watch’, by Sir John Floyer (1649-1734), an English provincial physician. It was introduced as early as 1707 as a ‘Physician’s Pulse Watch’ and was an instrument constructed to go for just one minute. At that time the making of a twenty-four hours watch with a seconds-hand presented great mechanical difficulties. Floyer’s invention was not widely adopted at the time. Attempts were also made to introduce a thermometer into practice, but again the construction of suitable instruments proved impossible.

Effective pulse watches and clinical thermometers did not penetrate into the general practice of Medicine till well into the nineteenth century. Two instrumental advances of first-class importance to Medicine were, however, introduced during the later eighteenth century. These were the methods of Percussion and Stethoscopy.

Percussion of the surface of the body yields notes of varying degrees of resonance. Its application has proved of great value to the physician in outlining the position of the organs and of lesions, especially those of the chest. It was invented by Leopold Auenbrugger (1722-1809), a Viennese physician who first introduced it in 1761. Like the thermometer, it was very slow in entering the general practice of Medicine.

Auenbrugger deserves great credit for his invention, but he did not work out its application with anything like the completeness that the Breton physician, René Théophile Hyacinthe Laënnec (1781-1826), applied to his ‘stethoscope’ (1819). Laënnec’s instrument was of the uni-tubular type that is now seldom seen. At first, indeed, he used a mere roll of paper. His idea was rapidly diffused into every country.

But Laënnec did far more than introduce a useful and convenient device into Medicine. He explored with extraordinary skill the physical signs in the chest which correspond to a large number of diseases. The major part of our chest-lore and much of the technique and nomenclature of chest examination come direct from him. Despite continual bad health and the shortness of his life, Laënnec’s brilliance and devotion to duty at a hospital in Paris enabled him to transmit his views and methods to many other physicians, both French and foreign. He is unquestionably among the greatest physicians of all time. Clinical medicine assumes with him a completely modern aspect. In reading his work one feels that, had he been called in consultation by a medical man of our own day, the two would have been able to understand each other perfectly, after only a little adjustment and explanation.

FIG. 79 is the complete instrument.

FIG. 80 is the instrument in section.

FIG. 81 is the ear-piece unscrewed.

FIG. 82 is the detachable chest-piece terminating in a thin metal tube.

]

§ 8. _Surgery and Obstetrics._

During the eighteenth century the improved knowledge of Normal and Pathological Anatomy was a great aid to the surgeon. The technique of Surgery was certainly improved. Operations were now being performed with success that could not before have been attempted. Nevertheless few important new principles were introduced until long after the nineteenth century had dawned. It is indeed probable that as a means of life-saving Surgery had an almost inappreciable effect on vital statistics until the advent of Anaesthesia and Antiseptics. Even the greatest surgeon of the eighteenth century, John Hunter, introduced no fundamental new surgical principles. True, the names of many surgeons of the period have become associated with operations invented or introduced by them, but it was not till after the advent of antiseptic methods that these were practised with full success. There are but two surgical matters in which advances of great significance can be said to have been made. These were the treatment of Venereal Disease and the treatment of Labor.

Syphilis, which existed in Europe in the later Middle Ages, had usually been confused with Leprosy and other conditions (p. 98). Its treatment by Mercury had been practised at least as early as the fifteenth century, perhaps as an inheritance from the Arabic-speaking physicians. During the sixteenth and seventeenth centuries various other remedies were tried (Fig. 33); much quackery arose around them. In the eighteenth century the accumulated experience of generations returned again to Mercury. Satisfactory methods of administration were evolved and the treatment became standardized. It hardly changed until the twentieth century.

FIG. 83. LYING-IN SCENE in the sixteenth century from a contemporary work on midwifery. Drinking and feasting is going on in the room where, in addition to the patient, there are two men, five women, and two children. A dog chews a bone on the floor, cooking is in progress in the adjoining room. Food and drink is being forced on the unfortunate patient herself. The whole scene, which is intended to portray an upper-class household, suggests carousal, disorder, and dirt, as well as ignorance of the most elementary principles of hygiene.

]

The treatment and care of women in Labor made considerable progress during the period of which we are treating. We have seen how there were advances even during the sixteenth century (p. 93) by such a writer as Paré. Works on obstetrics intended for women were often printed in the sixteenth century in France, England and Germany. Scientific obstetric

works were produced especially in France in the second half of the seventeenth century. The obstetric forceps was known, but was still a family secret. At the time and for long after, there was a great objection on the part of pregnant women to treatment by men. The midwives were for the most part ignorant, dirty, unskilful and superstitious, and the loss of life and health that resulted from their mishandling was enormous. The objection to the ‘man midwife’ was only gradually overcome, though his advent was unquestionably attended by a fall in the mortality. About the middle of the eighteenth century, moreover, the obstetric forceps came into wider use. One of the ablest and most successful of the obstetric physicians was William Hunter (1718-83), the brother of John Hunter.

FIG. 84 is the very dangerous and brutal _Speculum matricis_ used to force open the mouth of the womb in cases of difficult labor. A similar instrument has been used since antiquity to dilate wounds.

FIG. 85 is an even more terrible and powerful instrument, the _Apertorium_, provided with a sharp edge by means of which the mouth of the womb was violently cut or torn.

In the seventeenth century less heroic measures began to be used, and the obstetric forceps was introduced.

FIG. 86 shows a pair of obstetric forceps as used in the seventeenth century. The instrument is the direct ancestor of that now in use, which, however, is a vast improvement upon it. The obstetric forceps was invented by a member of an hereditary family of man midwives, at the beginning of the seventeenth century. The nature of the instrument was long kept a secret. This particular instrument was found by accident in 1813, having been hidden under the floor by a member of the family of the inventor.

]

Despite the absence of any great new principle in the surgery of the period, there can be no doubt that a new spirit was introduced by John Hunter (1728-93). His complex and interesting character demands better treatment than it has yet received. As an investigator his powers were superb, but, like Leonardo, he was handicapped at every turn by literary incoherence. Nevertheless, with him Surgery begins to appear, at last, as a real Science and not as a mere applied Art. Hunter brought to bear on the subject a mind stored with ideas drawn from Comparative Anatomy and Pathology. Quick to detect analogy, shrewd in his scientific judgments, tireless and unsparing of himself in his pursuit of truth, a victim of disease self-inflicted in the service of science to which he was tragically a martyr in his death, he shows as a heroic figure, rendered no less heroic by some very human failings. Fully to appreciate so incoherent a writer, it is unfortunately necessary to wade through many works written in his own clumsy and ill-arranged manner. To gain any real idea of this great personality we must consult the writings of his contemporary colleagues.

So far as actual advances are concerned, two may be connected with Hunter’s name. Firstly, in the treatment of the deadly condition known as ‘Aneurysm’ he introduced a method of operation which is still in vogue. Secondly, he enormously improved the method of making and ordering a museum. His monument is the Hunterian Museum in London, based on his specimens of which many may still be seen there. The museums of Natural History, as now constituted in all civilized countries, have been influenced by, if they have not been derived from, that which he literally gave his life’s blood to found. He was right when he said musingly in his illness, ‘You will not easily find another John Hunter.’

FIG. 87. JOHN HUNTER’S COUNTRY HOUSE at Earl’s Court, Kensington, before its demolition in 1886. This house was in the country in Hunter’s day, though its site is now a busy part of London. For many years he used it as a laboratory and menagerie, and much of his best work was done there.

]

§ 9. _The Beginnings of the Science of Vital Statistics._

Attempts to combat widespread disease and to improve the public health are to be found in the history of all civilizations, both ancient and modern. Nevertheless, the rational method cannot come into operation until it has exact data upon which to work. Such data may be numerically expressed, a fact first appreciated by the versatile English physician and inventor, Sir William Petty (1623-87), who is usually regarded as the father of the science of Political Economy. In 1662, and on many subsequent occasions, he joined a friend in issuing _Natural and Political Observations upon the Bills of Mortality_ of London. In this work he endeavored to deduce population, death-rates, disease prevalence, and other matters of vital statistics from the crude figures of the day. He was fully aware of the imperfection of his materials, and on this account he urged the necessity of providing a system and a government department for the collection of trustworthy statistics. In his _Political Arithmetick_ (1683), the basic work of modern Economics, he displays ideas of a very modern character. Among these is his view that the true wealth of a country is to be sought in its efficient man power.

A number of Petty’s fellow members of the Royal Society began to take interest in statistics. Chief among these was Edmund Halley, the astronomer (1656-1742). Toward the end of the century (1693) Halley produced a mass of statistics on the chances of life at various ages, designed for the estimation of the price of annuities. During the eighteenth century numerous writers devoted themselves to similar investigations. An important contributor to the mathematical basis of vital statistics was the French Huguenot and friend of Newton, Abraham de Moivre (1667-1754). His _Doctrine of Chances_ (1715) and his _Annuities upon Lives_ (1725) are important contributions to the subject. His celebrated hypothesis that among a body of persons over a certain age the successive annual decrease by death may be esteemed as nearly equal (that ‘the decrements of life are in arithmetical progression’) was under discussion for a century, but is now accepted.

In 1761 a Prussian clergyman, J. P. Süssmilch (1707-82), produced an extraordinary theological work, _The Divine Ordinance manifested in the Human Race through Birth, Death, and Propagation_. Its object was to exhibit God’s design in the constancy of the numerical relationships of vital statistics. Despite the motive--somewhat unpromising for a scientific treatise--the work is of great historic and scientific importance, for it was based upon a vast mass of statistics and showed a great advance in method. It stressed the importance of accurate data and the necessity for numerous observations, if reliable conclusions were to be drawn. From the time of the publication of the work of Süssmilch, the statistical study of population advanced rapidly. The basis of statistics was greatly improved by the introduction of the census system which was put into action in England in 1801.

The science of vital statistics was placed on a firm foundation by the Belgian astronomer Lambert Quetelet (1796-1874). His principal work, _On Man and on the Development of his Faculties, An Essay on Social Physics_, contains an account of his statistical researches on the development of the physical and intellectual qualities of man and on the ‘average man’ both physically and intellectually considered. He followed this in 1848 by his treatise, _On the Social System and the Laws which govern it_. In it he shows how the numbers representing the individual qualities of man may be grouped round the numbers referring to the average man in a way corresponding to the principles of the theory of probabilities. This conception, elaborated and further analyzed, has formed the basis of all subsequent researches in vital statistics.

§ 10. _Military, Naval, and Prison Medicine._

The eighteenth century saw some of Petty’s principles put into practice. There was, as yet, but one section of public life in which scientific principles of preventive medicine could be applied. Only in the Army and Navy were the sufferers from disease under adequate control and observation, and only there were proper statistics of sickness and health available. Thus, many of the most important movements in Preventive Medicine during the eighteenth century, both in England and other countries, were initiated by naval and military surgeons.

Among military medical reformers an important place is taken by a Scottish pupil of Boerhaave, Sir John Pringle (1707-82). He had a large military experience in the British army, occupied a position of great influence, and was able to get many of his views and reforms generally accepted. Pringle was among the first to see the importance of ordinary putrefactive processes in the production of disease, and quite the first to apply these principles in hospitals and camps. Important conclusions on these matters were published in his _Experiments upon Septic and Antiseptic Substances, with Remarks relating to their Use in the Theory of Medicine_, which appeared in 1750. He identified ‘gaol fever’ or typhus with ‘hospital fever’. He laid down important rules for the hygiene of camps which involved avoidance of marshes, proper drainage, and adequate latrines. His most permanent service was probably his suggestion that army hospitals should be regarded as neutral, and be mutually protected by belligerents. This great physician is a good illustration of the ‘new humanity’ which came into public life in the eighteenth century. In much of that movement one may feel the influence of that most humane of physicians, Hermann Boerhaave (pp. 140-1).

Hardly less important than the work of Pringle for the Army was that of his brother Scot, James Lind (1716-94), for the Navy. Lind was a pupil’s pupil of Boerhaave. He had a long naval experience and in 1753 wrote an important work on Scurvy, then a very common and fatal disease at sea. He demonstrated how this might be prevented by the adequate use of fresh fruit or, when this was not available, of lemon juice. Fresh water had always been a difficulty of sea voyages. Lind arranged for sea-water to be distilled for the purpose. He introduced rules for the prevention of typhus on ships, and made great improvements in naval hygiene. His essay of 1757 _On the most effectual means of preserving the Health of Seamen_ is a classic. He also wrote an important _Essay on Diseases of Europeans in Hot Climates_, which opened the campaign for the conquest of the tropics (p. 270).

Lind, like Pringle, is one of a type that is very fully represented in the eighteenth century. A worthy representative of that school was Captain James Cook (1728-79), the explorer, who adopted Lind’s principles. He established a record in one of his voyages to the South Seas. The voyage lasted three and a half years, and many hardships had to be endured, but out of 118 men only one died, and he was consumptive when he embarked from England. Of a different type was the Manchester health reformer, Thomas Percival (1740-1804), who worked to introduce the reforms of Pringle and Lind into civilian life. The work of Percival leads on naturally to Southwood Smith and Chadwick (pp. 193-5).

The eighteenth century was essentially a period of individual effort. The time was not yet ripe for public action on a large scale in matters of Hygiene. Pringle, Lind, and Percival had, however, their humanitarian parallels among prison reformers. Scientific attempts to improve the ventilation and sanitation of prisons had been instituted by the Rev. Stephen Hales (pp. 146-7). None brought greater devotion to the task than John Howard (1726-90), a native of London who spent his vigorous powers in investigating the prison system. His researches extended to the hospital, quarantine and prison systems of France, Flanders, Holland, Germany, Italy, Greece and Turkey (Fig. 88). His reports were directly instrumental in the improvement of the hygiene both of prisons and hospitals, as well as in the institution of special fever hospitals in many countries. Some aspects of Howard’s work were carried on by the great Quaker philanthropist Elizabeth Fry (1780-1845), others came within the field of activity of Southwood Smith and Chadwick (pp. 193-5).

The eighteenth-century humanitarian movement was active and had many able representatives in the United States. Foremost among them was Benjamin Franklin (1706-90), while in the ranks of Medicine none takes a higher place than Benjamin Rush of Philadelphia (1745-1813). Rush was particularly revolted by public punishments, to the abolition of which he devoted much energy. In matters of Hygiene Rush was ahead of his time. He wrote on the hygiene of troops and laid special stress on fresh air and cleanliness of body and mind as an aid to health. He had a peculiar horror and repulsion for alcoholic intemperance. He was responsible for the first systematic work on insanity published in America. He left a fine account of a Yellow Fever epidemic at Philadelphia, and he approached the truth in his view that the disease arose in Philadelphia itself and was not brought as an infection from without.

From John Howard’s _An Account of the principal Lazarettos in Europe_, Warrington, 1789.]

§ 11. _The Industrial Revolution._

During the eighteenth century the character of English civilization became modified by a factor which has since profoundly influenced all civilized countries. There was a rapid increase in the number and size of the towns. The main cause of this was the transformation of Industry by the use of mechanical power. The change that resulted in the life and outlook of the people was very profound. These changes and the causes that gave rise to them are usually spoken of as the ‘Industrial Revolution’. That revolution had effects that were both wider and deeper than followed any other such single upheaval in history. With the mechanical elements that were at the back of the Industrial Revolution, such as the improvements in transport, the invention of industrial machinery (Fig. 90), the enclosure of common land, the new position of agriculture, we are not here directly concerned. What does affect our story is the increasing urbanization of the population, which began early in the eighteenth century, increased rapidly soon after the middle of the eighteenth century, and has progressed continuously ever since. In this matter England is but a type, for all other civilized countries followed in her wake, though at a somewhat later date.

Along with the growth of towns and the increased population there was an increased demand for food. The country became better cultivated and better drained, and there were many improvements in agriculture. Thus, certain diseases began to diminish, notably Malaria, essentially a disease of undrained and ill-cultivated lands. The expulsion of this disease, as of Typhus, was the work of the nineteenth century (p. 283).

It is often assumed that the physical evils of life became accentuated by the rise of the great towns. Nevertheless, investigation shows that the opposite has been the case. During the eighteenth century men and women began to crowd into the great towns from the country. They were, in fact, right in their choice, for their chances of life there were greater than upon the land. In the rural districts infamous housing conditions, an overcrowding beyond anything which we now encounter, exposure to weather, uncertainty and fluctuation in the prices of commodities, low wages, unpassability of roads in winter time, inaccessibility of medical aids, combined to render life, and especially child life, more precarious than in urban areas.

FIGS. 89 and 90 illustrate the passage of the textile trade from home industry to factory work with the consequent break-up of the family as the labor unit. Textiles were the first important articles of commerce to be thus affected, but others rapidly followed. The pictures are typical of the Industrial Revolution.

]

The improvement of hygienic conditions in the towns began in England soon after the middle of the eighteenth century. Westminster obtained an Improvement Act in 1762, Birmingham in 1765, the City of London in 1766, Manchester in 1776, and most of the other provincial towns soon followed. As a result of such Acts noisome streams which were but open drains were covered in, the streets were paved and lighted, and the sewers improved. There were still many glaring defects of sanitation which have occupied and still occupy reformers, but by the end of the eighteenth century the general appearance of a street in one of the more advanced cities was much what it now is. The change from the medieval conditions of a century before was at least as great as the changes that have since taken place.

FIG. 91 shows how the population of England and Wales started to increase rapidly about 1750, with the beginning of the Industrial Revolution. The chart covers a period in which statistics were not exact. The figures for it have had to be estimated, but they are probably accurate as round numbers. The census returns are available from 1801.

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1910-12
_Age_ 1730-9 1740-9 1750-9 1760-9 1770-9 1780-9 1790-9 _Males_ _Females_
10 36·9 37·0 37·3 36·9 36·7 37·5 38·2 -- --
20 29·1 28·9 29·2 29·3 29·4 29·9 28·4 42·35 46·71
30 23·7 23·5 23·8 24·1 24·1 24·9 24·4 33·87 37·94
40 19·6 19·2 19·4 19·6 19·5 19·5 19·5 26·03 29·67
50 16·1 15·8 15·7 16·1 15·9 15·7 15·8 19·09 22·17
60 12·2 12·4 12·1 11·9 11·9 12·0 11·9 13·09 15·39
70 9·4 8·6 8·7 8·5 8·3 8·7 8·5 8·17 9·57
80 5·9 5·7 5·7 5·7 5·7 6·3 6·2 4·79 5·39

Showing the expectations of life in London for each decade from 1730-1800, with recent data for comparison.

_Age_ 1730-9 1740-9 1750-9 1760-9 1770-9 1780-9 1790-9 1911-12
10-20 6·5 5·9 5·9 7·1 8·2 7·1 6·5 --
20-30 17·5 17·6 17·2 17·9 17·3 16·4 15·1 3·7
30-40 27·1 26·3 26·1 25·2 25·0 23·9 23·7 6·2
40-50 36·6 38·6 35·9 36·3 35·5 35·4 34·3 11·7
50-60 45·5 47·9 45·7 42·1 45·0 44·7 44·6 21·1
60-70 61·4 63·4 63·7 64·4 62·8 64·7 64·1 40·3
70-80 83·7 98·3 96·4 101·8 105·0 101·7 104·4 87·3
80-90 143·1 150·4 151·0 153·0 152·7 153·0 155·1 181·9

Showing the death-rates at Age groups in London for each decade from 1730-1800, with recent data for comparison.

FIG. 91A. TABLES showing that vital conditions in the eighteenth century did not deteriorate but improved with the Industrial Revolution. ]

But if the streets had improved there was much under and around them which would horrify us now. Water-supply, as in London, was usually drawn mainly from surface wells and rivers. In most towns a continuous water-supply was unknown. Even when water mains existed, the supply to the houses was limited. Thus, even in the early nineteenth century London houses had a water-supply only three times a week, and then only for a few hours at a time. The water mains were often defective, and there was not always that clear distinction between a water main and a sewer that we now regard as desirable. Floods were a constant trouble in all riverside towns. Cesspools were in use even in London as late as the middle of the nineteenth century, and water-closets did not become general, even in the better houses, until about 1828. The methods of disposal of sewage hardly bear relation. In London the sewage simply polluted the rivers.

The improvement of such conditions as these could only be made by State action. The eighteenth century did well where individual activity was concerned. It was reserved for Southwood Smith (p. 193) and Chadwick (p. 194) to introduce into the sphere of practical political action the truth, set forth by Bentham (pp. 190-2), that all factors which influence the health of the country must be the concern of the Legislature.

We gladly pass from this darker picture to the Hospital and Dispensary Movement which took its rise about the middle of the eighteenth century. Many of the great hospitals both in England and in Continental countries were either founded or rebuilt about this time. Thus, the London Hospital was rebuilt in 1752, St. Bartholomew’s in 1730-53. Between 1700 and

1825 no less than 154 hospitals and dispensaries were founded in the British Isles. Though defective from the modern point of view, yet under the influence of the sanitary reformers, Hales (p. 146), Pringle (p. 169), Lind (p. 170), and Percival (pp. 170-1), these were incomparably better equipped, better ventilated and better found than such institutions would have been at the beginning of the eighteenth century. The notes of the industrious Howard (p. 171) give us a very complete picture of them, and one that is more favorable than might, perhaps, have been expected.

A defect of the hospitals of the time was certainly the nursing. This, however, was somewhat better in the Lying-in-Hospitals, where the services of a higher type of woman were available and where ladies served on the committee of management. The general state of the hospitals remained much the same until transformed by the changes in surgery and nursing in the second half of the nineteenth century, though a number of special fever hospitals and pest-houses were established.

Something must be said of the more prevalent diseases of the Industrial Revolution. Stress is often laid on the effect of urban conditions on child life. Yet there can be little doubt that historically the movement has been beneficial to it. This comes out well in the death-rates. Thus, in England in the period around 1740, before the industrial revolution had begun, about 75 per cent. of children born died before the age of five. In the period around 1800, when the industrial revolution had set in, the percentage of deaths had fallen to about 41. In the period 1915-24 it was about 14. Among the most characteristic diseases of children is Rickets. It is very difficult to trace the early history of this disease, but its incidence seems to have been very high about 1700, and to have fallen progressively throughout the eighteenth century. This fall, it has been suggested, was due to agricultural improvements which led to better supplies of better-fed meat. It was these improvements and better supplies that, in their turn, made the big towns possible.

We have already spoken of Scurvy on ships. It was, however, well known on land, especially in winter when green vegetables were not to be had. Lind (p. 170) in 1753 found it common in the land population. The advances in agriculture removed it altogether from the land diseases during the eighteenth century.

§ 12. _Control and Recognition of Epidemic Diseases._

Over one department of public health there was State supervision during the eighteenth century. The ports were guarded against the introduction of Epidemic Diseases, and especially against Plague. Throughout the eighteenth and early nineteenth century there was Plague in the Near East which extended at times to various parts of Europe. It was epidemic in Russia in 1709 and some 150,000 died of it. In 1719 it spread to Eastern Central Europe. One historic outbreak was at Marseilles and Toulon in 1720, when 90,000 died. The outbreak caused great alarm in England, but did not reach this country, nor has there since been any outbreak here. Quarantine is now regarded as antiquated, vexatious, inhumane, expensive, and ineffectual. It seems probable, however, that during the eighteenth century, when drastically enforced, as in France with the Marseilles epidemic, it had indeed the effect of keeping the disease within bounds. Incidentally, it led to the foundation of many plague hospitals or Lazarettos, of the conduct of some of which Howard (p. 171 and Fig. 88) speaks well.

During the eighteenth century Small-pox was never absent from this country. From time to time the disease became epidemic, and there were grave and fatal outbreaks. Thus, in 1774 there was an outbreak of small-pox at Chester. Next year an investigation was made of the degree to which the population had suffered. It was then found that before the outbreak there were in Chester only 15 per cent. who had not already had the disease. The incidence on those unprotected by a previous attack was 53 per cent., with a death-rate of about 17 per cent. of those actually infected and of about 9 per cent. of the entire unprotected population.

With the certainty of contracting small-pox before their eyes, men sought a way of getting it in a mild form. Outbreaks of small-pox varied greatly in virulence, and infection with a mild form would lead to protection from a graver one. In the East a method of direct inoculation of the disease from a patient suffering from a slight attack was widely in vogue from an early date. The practice attracted little attention in Europe until Lady Mary Wortley Montagu (1689-1762) studied it at Constantinople. It was then soon taken up in England, and became recognized on the Continent.

The efforts of Lady Mary in England were reflected on the other side of the Atlantic. The famous Puritan leaders, Increase Mather (1639-1723) and Cotton Mather (1663-1728), turning from their exploits against the witches, ardently urged the operation. In England the learned Dr. Richard Mead (1673-1754), an eminent and far-seeing physician who exercised very great influence on the medical world in his day, published in 1747 a work in which he supported the practice of inoculation with all the weight of his authority. During the subsequent half-century the practice spread widely. The operation was largely in the hands of specialists who were not always medical men.

Such was the state of affairs when the country practitioner Edward Jenner (1749-1823) came upon the scene. In 1796 a dairymaid became infected with a disease of the udders of cows, distantly resembling small-pox. She developed pustules on her hand. Jenner inserted a little of the matter from one of these into the arm of a boy of eight, who developed typical cow-pox. Jenner next inoculated this boy with small-pox, which, however, failed to develop. The evidence, so far as it went, was complete. It is an entire justification of what might seem nowadays to be a reckless experiment, that at that time inoculation of small-pox was a normal and effective defensive procedure. The disease of cows has since become known as Vaccinia, and the process of inoculating it as _Vaccination_.

FIG. 94. HAND OF DAIRYMAID infected with cow-pox from a cow’s udder. From Edward Jenner, _Inquiry into the Causes and Effects of the Variolae vaccinae, a Disease discovered in some of the Western Counties of England, particularly Gloucestershire, and known by the name of the Cow Pox_, London, 1798.

]

The discovery of vaccination, important though it be, is a mere trifle compared to the train of new work and new thought that has been opened out by it. The whole study of Immunity, which has now become an independent science, arises from it. The work of Pasteur (p. 225), Lister (p. 239), and Koch (p. 234), and a large part of modern therapy, are among the achievements of this movement.

Besides Plague and Small-pox, many other epidemic diseases became more clearly understood during the period we are considering. Among these was Scarlet Fever, the history of which is particularly interesting for the variations which it has shown in virulence. It first became clearly recognizable as a mild disease without prominent symptoms about 1650. Good observers in the half-century that followed considered it a new disease. In England it continued to be of little importance till about 1748, when it began to be associated with grave throat symptoms and to be confused with Diphtheria. This phase continued for about ten years. The virulence then dropped and the disease continued of slight consequence till 1785. It then grew virulent again and remained so till about 1808. The malignancy then fell again and remained low for about thirty years. It rose about 1837 and from then till 1884 it was one of the great killing diseases, especially of childhood. Since then, the mortality from it has steadily decreased.

During most of its history Scarlet Fever has been liable to greater or less confusion with Diphtheria. The clinical distinction was first clearly made in 1826 by Pierre Bretonneau of Tours (1771-1862), who gave Diphtheria its present name. The same French physician performed the first successful tracheotomy in a case of Diphtheria. He is also known for pioneer work in the recognition of Typhoid Fever.

VI

PERIOD OF SCIENTIFIC SUBDIVISION

(FROM ABOUT 1825 ONWARDS)

§ 1. _Origins and Implications of Scientific Specialization._

We have seen how the philosophy of Newton, with its implication, the Reign of Law, which is the Uniformity of Nature, has come to pervade scientific thought (p. 137). Now, before Newton as after him, there were certain natural divisions of scientific activity corresponding, in some degree, to the types and faculties of men. Since Science first began there have been Mathematicians, Biologists, Physical Experimenters, because in fact the particular powers which enable a man to reach distinction in one of these departments are of less value in the others. Until the period of which we are now to treat, investigators were accustomed to explore at large within these great departments. Such specialist professions as Actuarial Calculators, Economic Entomologists, Physical Chemists, or, in the department of Medicine, Medical Statisticians, Aural Surgeons, or Vaccine Therapists--familiar to us now--were unknown and undreamt of then. This subdivision is a new thing, and is a characteristic product of the period of which we have now to treat. The subdivisions, unlike those of old, are largely artificial. Thus, the Aural Surgeon who deals with the organ of hearing cannot be separated clearly by his training, his powers and faculties, his operative skill, nor even perhaps by his field of work, from the Stomatologist who deals with the mouth, or the Rhinologist who deals with the nose. Nevertheless these minute subdivisions are convenient and beneficent in medical as in other departments. The question of scientific specialization is so important and characteristic that we must examine it a little farther.

It is often thought that, since no man can compass all knowledge, this scientific subdivision is merely an attempt to compass a part of that growing mass of knowledge which is becoming progressively less compassable in its entirety. The movement, however, both in origin and development, is less simple than this, for there never was a time when a man could know all that was known about his world. In this respect our own age is even as other ages. Were the view philosophically tenable--which it is not--that Science becomes yearly less comprehensible, our outlook would be gloomy indeed. For since there is no evidence of any increase in the mental capacity of the human race--at least in historic time--such a view would imply a progressive diminution in the number of those competent to treat any wide scientific area, and a corresponding progressive separation from each other of minds with scientific insight. Fortunately such conditions do not prevail; the view that they do is simply due to a gross, yet widespread, misconception of the nature of Science.

Equally fallacious is the idea, which has become diffused by the existence of scientific specialization itself, that the progress of any science is to be measured by the mass of observations that its votaries have succeeded in accumulating. This is far from being the case. The advance of a science is measured by the degree with which it succeeds in bringing a multiplicity of observations under general laws. Judged by this standard, we should probably rate very highly, for example, the present state of what is called _Demography_, the study of the life conditions of communities, while we should rank much less highly, for example, the present state of the study of Aural Surgery. Yet, for one publication on Demography there must be many on Aural Surgery. In the one case, however, the accumulation of knowledge follows a well-directed and rational scheme. In the other it is prompted and occasioned by the immediate needs of individual sufferers. This must not be considered as derogatory to those whose task it is to treat the sufferers. The point is that the one department, of its nature, exhibits the rational spirit better than does the other.

Since Rational Medicine is the subject that we treat here, we shall select for discussion those departments which best illustrate its spirit. This does not imply, and is not meant to imply, any belittlement of the less fortunate departments. On the contrary, the less any scientific department has succeeded in eliciting general laws, the more necessary it is that those most capable for the prosecution of such advance should devote their attention to that department. It may, indeed, reasonably be urged that a leading defect in our scientific organization is that men of scientific insight crowd to just those studies where their special powers have already been best exhibited.

In previous chapters, dealing with more remote times, we have been able to place our facts in historic perspective. Despite the enormous mass of scientific literature dating from the seventeenth, eighteenth, and early nineteenth centuries, there is no real obstacle to selecting what is most important in it. True, it is beyond the power of any one student to examine all this literature at first hand, but it has been arranged and indexed, posterity has passed its verdict, and the historian can find his way through the thicket. It is also true that important advances are sometimes forgotten, as happened to Mayow’s discovery of Oxygen in the seventeenth century (pp. 126, 151), which was repeated by Priestley a hundred years later (p. 154). But the fact that we know of such neglected discoveries shows that, however unjust the fates may have been to Mayow, yet his influence has not been underestimated by later historians. The History of Science, therefore, can up to a certain point be written along the same lines as political or economic history.

The face of affairs changes, however, when we pass into a period which differs for different topics, but may be roughly defined as beginning somewhere between about 1820 and about 1870. We then begin to encounter the very questions with which men of Science are occupied in our own time. Since many of these questions still remain unsettled, it is impossible for the historian to say with certainty which are the most fruitful lines of work. The most he can hope to do is to distinguish the most influential and stimulating thinkers and observers from those who have been less so, and to say something about the ideas with which the more important schools of thought were instinct.

When we look into the origin of the system of specialization, whether in Medicine or in any other department of Science, we shall find certain philosophical tendencies at work of which the modern man of Science is the heir, though often the unconscious and sometimes the ungrateful and even the misunderstanding heir. Neither men of Science nor medical men are always philosophers, or at least not always consciously so. Nevertheless, they are as surely influenced by the streams of thought of their time as they are by their heredity and their physical environment. The general tendencies of Medicine in this or in any other age cannot be interpreted without some reference to the intellectual atmosphere in which it has arisen and in which it has flourished.