Chapter X: Part 10

Rats are exceedingly fond of malt, and in malt houses and breweries
constant watchfulness is needed to prevent losses. Mills, elevators,
and warehouses in which grain and feed stuffs are stored are subject
to constant invasion by rats and mice.

A full-grown rat consumes about 2 ounces of grain daily. A half-grown
rat eats nearly as much as an adult. Fed on grain, therefore, a rat
eats from 45 to 50 pounds a year. The cost depends somewhat on the
kind of grain. If wheat, the value is 60 to 75 cents; if oatmeal,
about $1.80 to $2. Several feeders of horses in Washington, D. C.,
estimated the cost of keeping each rat on their premises at $1 a year.
Even though half the grain eaten is waste, the direct loss from this
source to feeders is enormous.

MERCHANDISE IN STORES AND WAREHOUSES.

The loss from depredations of rats on miscellaneous merchandise in
stores, markets, and warehouses, is second only to the losses on
grains. Not only are food materials of every kind subject to attack,
but the destruction of dry goods, clothing, books, leather goods, and
so on is equally serious. Merchandise other than foodstuffs is usually
destroyed for making nests, but books and pamphlets, especially the
newly bound, and some other articles, furnish food in the glue, paste,
oils, or paraffin used in their manufacture. Some kinds of leather
have a peculiar attraction for rats, while others are never touched.
Shoes are seldom gnawed unless they have cloth uppers or are made of
kid. New harnesses are not often attacked, except collars, which
contain straw, and cruppers, which are stuffed with flaxseed. Old
harness leather is salty from the perspiration of horses, and rats and
mice gnaw it for this reason. Kid gloves and other articles made of
similar leather are often destroyed by rats.

Lace curtains, silk handkerchiefs, linens, carpets, mattings, and
other dry goods in stores are often attacked by rats. Some of the
stuffs contain starch, which serves as food, but most of them furnish
nesting materials only. A slight injury makes these articles
unsalable; this is especially true of white goods, which are easily
ruined by soiling. Nearly all large dry goods and department stores
suffer heavy losses from rats. Grocers, druggists, confectioners, and
other merchants also have similar experiences, and to the direct
losses must be added the sums expended in fighting the pests.

MERCHANDISE IN TRANSIT.

Merchandise billed for shipment often lies for days in stations and
warehouses or on wharves, where depredations of rats and mice cause
heavy losses to shippers and consignees. Similar losses occur on boats
carrying merchandise from port to port.

Fruits and vegetables in transit on steamboats are often destroyed or
damaged by rats. Tomatoes, cucumbers, sweet potatoes, bananas,
oranges, grape fruit, peanuts, and similar produce shipped by water
from the South, especially in winter, reach northern markets with a
large percentage of loss.

In view of the practicability of destroying rats on ships by
fumigation, and the ease with which rat-proof compartments for stowing
produce can be constructed, it would seem that losses of this nature
should be entirely prevented.

POULTRY AND EGGS.

Aside from disease, the greatest enemy of poultry is the rat. The loss
from rats varies with their abundance and the care taken to exclude
them from the poultry yard. The magnitude of the damage is not
generally known, because much of it is blamed on other animals,
particularly minks, skunks, and weasels. Much of the injury occurs at
night, and the actual culprit is seldom detected. Farmers have heard
that minks, skunks, and weasels prey upon poultry. What more natural
than to conclude that one of these animals is doing the mischief,
especially if one has been seen about the premises?

Rats often prey upon small chicks, capturing them in the nests at
night or even about the coops in the daytime. The writer has known
rats to take nearly all the chicks on a large poultry ranch, and over
a large section of country to destroy nearly half of a season’s
hatching. Young ducks, turkeys, and pigeons are equally liable to
attack, and when rats are numerous, are safe only in rat-proof yards.

A writer in a western agricultural journal states that in 1904 rats
robbed him of an entire summer’s hatching of three or four hundred
chicks.[CD] A correspondent of another newspaper says, “Rats destroyed
enough grain and poultry on this place in one season to pay our taxes
for three years.”[CE] When it is remembered that the poultry and eggs
marketed each year in the United States have a farm value of over
$600,000,000, it will be seen that a small percentage of loss
represents an enormous sum.

Footnote CD:

Homemaker (Des Moines, Iowa), May 27, 1907.

Footnote CE:

Missouri Valley Farmer, April, 1907.

The destruction of eggs by rats is great, not only on the farms where
they are produced, but also in the markets. Commission men and grocers
complain of depredations upon packed eggs. The animals break and eat a
few eggs at the top of a case and the broken yolks run down and soil
the eggs below. Then, too, rats carry away unbroken eggs, displaying
much ingenuity in getting them over obstacles, as up or down a
stairway.

A commission merchant in Washington, D. C., states that he once stored
100 dozen eggs in a wooden tub in his warehouse and left them for
nearly two weeks. He then found that rats had gnawed a hole through
the tub, just under the cover, and had carried away 71½ dozen, leaving
neither pieces of shell nor stains to show that any had been broken.

Besides their destruction of eggs and young fowls, rats eat much of
the food put out for poultry. They are destructive also to tame
pigeons and their eggs, but particularly to young squabs. They climb
the wire netting and gain entrance to the cages through the same
openings by which the pigeons come and go. Fanciers are often put to
great trouble to protect their pigeons from rats, and because of these
pests some of them have abandoned the business.

GAME AND WILD BIRDS.

The rat is the most serious pest in European game preserves. A writer
in Chambers’s Journal says:

In a closely preserved country at the end of an average year the
game suffers more from the outlying rats of the lordship than from
the foxes and mustelines together. The solitary rats, whether males
or females, are the curse of a game country. They are most difficult
to detect, for in a majority of cases their special work is supposed
to be done by hedgehog, weasels, or stoat.[CF]

Footnote CF:

Chambers’s Journal, vol. 82, p. 64, January, 1905.

The propagation of game birds is becoming a promising industry in the
United States. The difficulties of the business are not yet fully
known, but the rat is an enemy with which the raiser of game will have
to contend. The animal has already proved itself a foe in American
pheasantries.

Our wild native game birds are less subject to rat depredations than
birds kept in confinement. The nests of ruffed grouse are in
woodlands; those of the prairie hen and related species are on plains
remote from the haunts of rats. The quail, however, often makes its
nest within the summer range of rats, which destroy many of its eggs.

Rats are said often to destroy the nests of wild ducks, woodcock, and
other marsh birds. Terns have been entirely driven from their nesting
grounds in this way. In England the common tern was extirpated from
the Thames marshes; and on Loggerhead Key, Tortugas Islands, off the
Florida coast, rats recently nearly exterminated a colony of least
terns by destroying the eggs.

The nests of many ground-nesting and other song birds are robbed by
rats. Crows, jays, snakes, and skunks are blamed for most of the
destruction and the actual offender seldom suspected. While the other
animals named do part of the mischief, the rat is a more serious foe
of song and game birds than any of these.

FRUITS AND VEGETABLES.

A well-known form of damage by rats is the destruction of fruits and
vegetables in cellars and pits. Apparently no garden vegetable or
common fruit is exempt from attack. But the rat does not confine its
depredations to stored fruits and vegetables. It attacks ripe
tomatoes, melons, cantaloupes, squashes, pumpkins, sweet corn, and
many other vegetables in the field; and often the depredations are
attributed to rabbits or other animals, which may or may not be
concerned in the mischief.

Rats are fond of the small fruits, eating not only the fallen but
climbing vines and canes to obtain the ripe grapes or berries. They
eat also apples, pears, cherries, and other fruits. The brown rat,
while not so expert as the black or the roof rat, readily climbs trees
and obtains fruit even at the extremities of the branches.

Among tropical fruits injured by rats are oranges, bananas, figs,
dates, cocoanuts, and especially the pods of cacao (_Theobroma
cacao_), from which chocolate is manufactured. H. N. Riddey, writing
of his experiences on the island of Fernando do Noronha, South
America, mentions the destructiveness of rats in this penal colony.
They climb the cocoanut palms and papaw trees to devour the fruit, and
do mischief in melon patches. To lessen the evil, each convict was
required to bring in a certain number of dead rats, and battues were
held monthly to satisfy the requirement. Sometimes the number killed
in a single hunt reached 20,000.[CG]

Footnote CG:

Zoologist, vol. 46, p. 46, 1888.

Fruits and vegetables grown under glass are subject to injury by rats.
The animals usually find entrance to greenhouses by way of openings
for pipes or drains.

FLOWERS AND BULBS.

Rats attack seeds, bulbs, and the leaves, stems, and flowers of
growing plants, whether in the greenhouse, propagating pits, or
elsewhere. Of flowering bulbs, the tulip suffers most from rats.
Hyacinths also are eaten; but, probably because they are slightly
poisonous, narcissus and daffodil bulbs escape injury. Rats eat pinks,
carnations, and roses, cutting the stems off clean. They denude
geraniums of both flowers and leaves. They attack the choicest blooms
of chrysanthemums and carnations in markets, stores, and exhibition
rooms, causing heavy losses.

FIRES.

Rats and mice cause many fires. Several specific instances have been
reported by the fire department of the city of Washington within the
past two or three years. It is likely that some of these fires are
caused by rats gnawing matches. The animals are fond of paraffin,
which is often used to protect match heads. They carry the matches to
their nests, which are composed of paper and other combustible
materials, and the conditions for a conflagration are ready. Since the
heads of matches contain from 14 to 17 per cent of phosphorus, actual
gnawing is not required to ignite them, but heat or friction from any
cause may suffice.

Fires in mills or warehouses have sometimes been traced to the
spontaneous ignition of oily or fatty rags and waste carried under
floors by rats. Cotton and woolen mills are said to be peculiarly
subject to fires of this kind.

Sometimes rats cause fires by gnawing through the lead pipes leading
to the gas meter. Workmen or others, searching for the leak,
accidentally ignite the gas. Phillips’s warehouse, London, was twice
badly damaged by fires originating in this way, and in several
instances the sleeping inmates of houses have been in danger of
asphyxiation by gas freed in this manner.

The most common way in which rats and mice cause fires is by the
destruction of the covering of electric light wires under floors or in
partition walls. A considerable percentage of the enormous fire losses
in the United States is caused by defective insulation of wires. After
wires are once in position rats are the chief agents in impairing the
insulation. These animals do much mischief also by gnawing off the
coverings of telephone wires. In the case of electric light wires the
covering is probably used by the rats for nesting material, but
frequently the paraffin in the insulation is the object of attack.

BUILDINGS AND FURNITURE.

Rats seem to be able to gnaw through almost any common material except
stone, hard brick, cement, glass, and iron; neither wood nor mortar
suffice to keep them out of bins or rooms. They sometimes gnaw through
walls or doors in a single night. In the same way they enter chests,
wardrobes, bookcases, closets, barrels, and boxes. Almost every old
dwelling bears evidence of its present or former occupancy by rats.
Often the depreciation of houses and furniture is largely due to marks
left upon them by rats—marks that paint and varnish can not hide.

Damage to dwellings by rats is a large item. The decay of sills and
floors is hastened by contact with moist soil brought up from rat
burrows. Ceilings, wall decorations, and floor coverings are flooded
by leaks in lead pipes or wooden tanks gnawed by rats. Bricked areas
and even foundations are undermined and ruined by rats. All this is
real waste and a constant drain on the resources of the country.

MISCELLANEOUS.

A few instances of miscellaneous damage by rats may be mentioned to
show the great variety of mischief chargeable to the animals.

A Washington, D. C., merchant reported that at one time rats in his
store destroyed 50 dozen brooms worth $2.50 a dozen. In another store,
in a single night, they broke $500 worth of fine chinaware on shelves
and tables. A dealer in harness reported the loss of $400 worth of
collars in one season. The manager of a restaurant complained of an
average loss of $30 a month in table linen ruined by rats and mice. A
hotel reported the destruction of $75 worth of linen in a month.

At Mobile, Ala., in March, 1908, lost jewelry worth $400 was recovered
from a rat’s nest in the home of Señor Viada.

In London rats at one time killed all but 11 out of an aviary of 366
birds.

At Hamburg, Germany, Carl Hagenbeck once had to kill three young
African elephants because rats had gnawed their feet, inflicting
incurable wounds.

Rats often gnaw the hoofs of horses until they bleed. They kill young
lambs and pigs, and have been known to gnaw holes in the bodies of
very fat swine, causing death.

Like the muskrat, the brown rat often burrows into embankments and
dams, causing serious breaks.

The rat is one of the greatest enemies with which the sugar planter
has to contend, destroying acres of growing cane.

In rice plantations rats not only break down and destroy the growing
crops, but burrow into the dikes and flood the fields at the wrong
season.

On the London docks and on shipboard ivory is often badly damaged by
rats. They select for attack the greenest tusks, which are the more
valuable.

Mail sacks and other kinds of bagging are greatly injured by rats. The
consequent loss and necessary outlay for repairs are a large item in
post-office expenditures and in mills and other places where bagging
is used.

About the year 1616 rats caused a two years’ famine in the Bermudas.
In the southern Deccan and Mahratta districts of India rats ate a
large part of the scant crops of 1878 and 1879, and were regarded as
in a great measure responsible for the severe famine which
followed.[CH] A writer in Chambers’s Journal stated that the Dutch
abandoned the Isle of France (Mauritius) in 1610 because of the great
abundance of rats.[CI]

Footnote CH:

Brit. Med. Journ., p. 623, September 15, 1905.

Footnote CI:

Chambers’s Journal, vol. 21, p. 244, 1854.

AMOUNT OF LOSSES CAUSED BY RATS.

The damage done by a single rat varies greatly with the circumstances.
We have already stated that the cost of feeding a rat on grain varies
from 60 cents to $2 a year. Assuming that much of the rat’s food is
waste, each rat on a farm will cause a loss of over 50 cents a year.
In cities the damage by a single rat probably averages more than in
the country. Hotel managers and restaurant keepers state that $5 a
year is a low estimate of the loss inflicted by a rat. In making an
estimate it should be remembered that the rat is to be charged not
only with the food it actually consumes but also with what it destroys
or pollutes and renders unfit for use.

If an accurate census of the rats in the United States were possible,
and if the minimum average loss caused by a rat were known, an
estimate of the total annual losses from their depredations could be
made. It was on such a minimum basis that the Incorporated Society for
the Destruction of Vermin arrived at their total estimate of
£15,000,000 ($73,000,000) as the yearly losses from rats in Great
Britain and Ireland. Three propositions were assumed: first, that in
cities and villages the number of rats equals the population; second,
that in the country there is at least one rat for every acre of
cultivated land; third, that each rat in the kingdom inflicts a damage
of at least a farthing per day. Circulars asking whether these
assumptions are excessive were distributed throughout the country.
From 90 to 99 per cent of the replies fully indorsed each of the
assumptions.

It can readily be seen that the English basis of estimate would not
apply to farm conditions in the United States, where the area in the
twelve leading crops alone is over 250,000,000 acres. On a basis of a
rat per acre and damage of a farthing per day the annual loss on this
area would be $450,000,000, a sum much too great for serious
consideration. However, in the more thickly populated parts of the
country an estimate of one rat per acre would not be excessive; and it
is probable that in most of our cities there are quite as many rats as
people. Yet it would be unsafe, owing to our vast territory and
varying conditions, to make these assumptions the basis for
conclusions.

Over a year ago the writer made an attempt to investigate actual
conditions, and thus arrive at an estimate of the total damage by rats
in the cities of Washington and Baltimore. From the data obtained the
direct annual damage in the two cities was calculated at $400,000 and
$700,000, respectively. The Census Bureau in 1906 estimated the
population of these cities at 308,000 and 554,000, respectively. If
the estimates of damage were correct, the average loss for each person
is $1.27 a year; and, on the same basis, the 28,000,000 of urban
population in the United States (census of 1900) sustains an annual
direct injury of $35,000,000 from rats. This is considerably lower
than on the English assumption, which would make the losses in our
cities over $50,000,000.

Denmark (population 2,500,000) has an estimated rat bill of about
$3,000,000 a year, or $1.20 a person. Germany (population 56,000,000)
is said to sustain a loss from rats of 200,000,000 marks ($47,640,000)
a year, or about 85 cents for each person. The per capita estimate for
the United Kingdom is about double that made for Germany. In France
the loss from rats and mice for a single year (1904) was placed at
$38,500,000, or a little over a dollar for each of its 38,000,000
inhabitants. These estimates are supposed to include only direct
losses, but they vary enough to show that no common basis can be
assumed for all countries. With present information, therefore, any
attempt to state the amount of loss from rats in the United States
would be largely guesswork. Considering the population and wealth of
the country, however, and the vast area over which rats are abundant,
it is not unreasonable to conclude that in the United States the
losses from rats amount to much more than in any of the other
countries named.

INDIRECT LOSSES.

To the direct losses caused by rats must be added the cost of fighting
the animals and of protecting property from them. In our larger cities
a number of so-called expert rat catchers are to be found, who operate
with dogs, ferrets, traps, poisons, or other means, and who have an
extensive clientage among merchants, hotel managers, and others. These
pay the rat catcher a yearly or monthly stipend to keep their premises
free of rats and mice. Some of the large establishments pay $200 to
$600 yearly for such service. While the agreements are seldom kept in
full, the clients are usually satisfied that results warrant the
expense. Even when no contractor is employed, merchants are at expense
for traps, poisons, the keep of cats or dogs, and other means of
fighting rats. The same is true in less degree of nearly every
householder.

The cost of protecting property from rats is no small item. It
increases the expense of nearly all building, but it greatly reduces
direct losses from the animals. The economy of rat-proof construction
is everywhere manifest, in city or country, and the necessity for it
can not be too strongly emphasized.

Depreciation of property and loss of rents and custom are items not
generally thought of in connection with rat damage. A few years ago
the writer knew of almost an entire block of city houses that remained
untenanted for several months, because infested by rats. As the houses
were otherwise desirable, the loss of rent to the owners was probably
nearly $2,000. The presence of rats in markets, hotels, and
restaurants inevitably results in loss of custom, besides the direct
damage by the rodents.

From every point of view the keeping of rats is exceedingly expensive,
and the sooner our population can be made to realize the enormous
drain upon our resources caused by these rodents the sooner can
concerted measures for their destruction be made effective.

THE RAT IN RELATION TO INTERNATIONAL SANITATION.

By Asst. Surg.-Gen., JOHN W. KERR,

_Public Health and Marine-Hospital Service_.

Rats, like man, had their origin in Asia, from which continent they
have finally become disseminated throughout the world. They, too, like
man, are great travelers, and therefore prey on the commerce of the
ships in which they are carried. For this reason, and on account of
the fact that they are subject to plague and may transmit the disease
from one country to another, these animals have an influence on
international policy, and their control aboard ships is an
international problem.

It has been estimated that there are as many rats as there are human
beings, and that each rat causes each day a loss by the destruction of
material of at least half a cent.

Assuming that the rat population aboard ships is as great as the human
population—and my experience gained during the fumigation of ships to
kill rats convinces me that on the whole it is greater—some idea may
be had of the enormous migrations of rats and the toll they exact for
food from international commerce. Some idea can also be had of the
danger of rats in transmitting plague when it is remembered that 51
countries have been infected with the disease since the present
pandemic began in Canton, China, in 1894, and when it is known that at
least 146 ships have had plague infection on board during that time.

During the International Sanitary Conference of Paris in 1903 the
influence of the rat in transmitting plague was borne in mind, and the
international sanitary agreement, which was signed ad referendum
December 3, 1903, requires the destruction of rats aboard
plague-infected ships, recommends it on ships suspected of being
plague infected, and permits it on ships indemne from plague. The ship
is considered indemne from plague which, although coming from an
infected port, has had neither death nor case on board either before
departure, during the voyage, or at the moment of arrival.

The International Sanitary Convention signed at Washington, October
14, 1905, follows the text of the Paris convention, with respect to
plague, consequently embodying similar requirements and
recommendations as follows:

ART. XX. _Classification of ships._—A ship is considered as infected
which has plague, cholera, or yellow fever on board, or which has
presented one or more cases of plague or cholera within seven days,
or a case of yellow fever at any time during the voyage.

A ship is considered as suspected on board of which there have been
a case or cases of plague or cholera at the time of departure or
during the voyage, but no new case within seven days; also such
ships as have lain in such proximity to the infected shore as to
render them liable to the access of mosquitoes.

The ship is considered indemne which, although coming from an
infected port, has had neither death nor case of plague, cholera, or
yellow fever on board, either before departure, during the voyage,
or at the time of arrival, and which in the case of yellow fever has
not lain in such proximity to the shore as to render it liable, in
the opinion of the sanitary authorities, to the access of
mosquitoes.

ART. XXI. Ships infected with plague are to be subjected to the
following regulations:

1. Medical visit (inspection).

2. The sick are to be immediately disembarked and isolated.

3. Other persons should also be disembarked, if possible, and
subjected to an observation,[CJ] which should not exceed five days,
dating from the day of arrival.

Footnote CJ:

The word “observation” signifies isolation of passengers, either
on board ship or at a sanitary station, before being given free
pratique.

4. Soiled linen, personal effects in use, the belongings of crew[CK]
and passengers which, in the opinion of the sanitary authorities are
considered as infected, should be disinfected.

Footnote CK:

The term “crew” is applied to persons who may make, or who have
made, a part of the personnel of the vessel and of the
administration thereof, including stewards, waiters, “cafedji,”
etc. The word is to be construed in this sense wherever employed
in the present convention.

5. The parts of the ship which have been inhabited by those stricken
with plague, and such others as, in the opinion of the sanitary
authorities, are considered as infected, should be disinfected.

6. The destruction of rats on shipboard should be effected before or
after the discharge of cargo, as rapidly as possible, and in all
cases with a maximum delay of forty-eight hours, care being taken to
avoid damage of merchandise, the vessel, and its machinery.

For ships in ballast, this operation should be performed immediately
before taking on cargo.

ART. XXII. Ships suspected of plague are to be subjected to the
measures which are indicated in Nos. 1, 4, and 5 of Article XXI.

Further, the crew and passengers may be subjected to observation,
which should not exceed five days, dating from the arrival of the
ship. During the same time the disembarkment of the crew may be
forbidden, except for reasons of duty.

The destruction of rats on shipboard is recommended. This
destruction is to be effected before or after the discharge of
cargo, as quickly as possible, and in all cases with a maximum delay
of forty-eight hours, taking care to avoid damage to merchandise,
ships, and their machinery.

For ships in ballast this operation should be done, if done at all,
as early as possible, and in all cases before taking on cargo.

ART. XXIII. Ships indemne from plague are to be admitted to free
pratique immediately, whatever may be the nature of their bill of
health.

The only regulation which the sanitary authorities at a port of
arrival may prescribe for them consists of the following measures:

1. Medical visit (inspection).

2. Disinfection of soiled linen, articles of wearing apparel, and
the other personal effects of the crew and passengers, but only in
exceptional cases when the sanitary authorities have special reason
to believe them infected.

3. Without demanding it as a general rule, the sanitary authorities
may subject ships coming from an infected port to a process for the
destruction of the rats on board before or after the discharge of
cargo. This operation should be done as soon as possible, and in all
cases should not last more than twenty-four hours, care being taken
to avoid damaging merchandise, ships, and their machinery, and
without interfering with the passing of passengers and crew between
the ship and the shore. For ships in ballast this procedure, if
practiced, should be put in operation as soon as possible, and in
all cases before taking on cargo.

When a ship coming from an infected port has been subjected to a
process for the destruction of rats, this process should only be
repeated if the ship has touched meanwhile at an infected port, and
has been alongside a quay in such port, or if the presence of sick
or dead rats on board is proven.

The crew and passengers may be subjected to a surveillance, which
should not exceed five days, to be computed from the date when the
ship sailed from the infected port. The landing of the crew may
also, during the same time, be forbidden except for reasons of duty.

Competent authority at the port of arrival may always demand, under
oath, a certificate of the ship’s physician, or in default of a
physician, of the captain, setting forth that there has not been a
case of plague on board since departure, and that no marked
mortality among the rats has been observed.

ART. XXIV. When upon an indemne ship rats have been recognized as
pest stricken as a result of bacteriological examination, or when a
marked mortality has been established among these rodents, the
following measures should be applied:

1. Ships with plague-stricken rats:

(_a_) Medical visit (inspection).

(_b_) Rats should be destroyed before or after the discharge of
cargo, as rapidly as possible, and in all cases with a delay not to
exceed forty-eight hours; the deterioration of merchandise, vessels,
and machinery to be avoided. Upon ships in ballast, this operation
should be performed as soon as possible, and in all cases before
taking on cargo.

(_c_) Such parts of the ship and such articles as the local sanitary
authority regards as infected, shall be disinfected.

(_d_) Passengers and crew may be submitted to observation, the
duration of which should not exceed five days, dating from the day
of arrival, except in special cases, where the sanitary authority
may prolong the observation to a maximum of ten days.

2. Ships where a marked mortality among rats is observed:

(_a_) Medical visit (inspection).

(_b_) An examination of rats, with a view to determining the
existence of plague, should be made as quickly as possible.

(_c_) If the destruction of rats is judged necessary, it shall be
accomplished under the conditions indicated above in the case of
ships with plague-stricken rats.

(_d_) Until all suspicion may be eliminated, the passengers and crew
may be submitted to observation, the duration of which should not
exceed five days, counting from the date of arrival, except in
special cases, when the sanitary authority may prolong the
observation to a maximum of ten days.

ART. XXV. The sanitary authorities of the port must deliver to the
captain, the owner, or his agent, whenever a demand for it is made,
a certificate setting forth that the measures for the destruction of
rats have been efficacious and indicating the reasons why these
measures have been applied.

To be in conformity with these agreements regarding the destruction of
rats, quarantine authorities may demand the fumigation of infected and
suspected ships; suspected ships within the meaning of the treaties
being those on board of which there have been a case or cases of
plague at the time of departure or during the voyage, but no new case
within seven days. In the case of indemne ships, on the other hand,
without demanding it as a general rule, the sanitary authorities may
subject them to fumigation to kill rats. When upon such ships rats
have been recognized as pest stricken, as a result of bacteriological
examination, or when a marked mortality has been established among
these rodents, fumigation is prescribed.

While the classification of ships and the limitations placed on
quarantine procedures in relation thereto, as contained in existing
international sanitary agreements, is more apparent than real, there
appears to be a lack of exactness with respect to the destruction of
rats necessary for the prevention of the importation of plague from
one country to another.

Since the adoption of the international sanitary agreement of Paris in
1903, some of the unproven convictions of that time regarding the rôle
of rats and fleas in the transmission of plague have been proven to be
positive facts. Many epidemiological observations and exact scientific
experiments have demonstrated particularly the importance of the rat
in the propagation of plague and the rôle of the flea as the carrier
of infection from rat to rat and from rats to man.

At the same time there has been a growing conviction that other
agencies, such as passengers, baggage, and merchandise play a very
minor rôle in the dissemination of plague. It is of interest,
therefore, to review the efforts being made at the more important
seaports to exterminate rats, as well as the methods being employed to
that end.

INQUIRY INTO THE CRUSADE AGAINST RATS THROUGHOUT THE WORLD.

The first law in modern times aiming at the destruction of rats
appears to have been enacted in Barbados in 1745.[CL] According to
Boelter this act was incorporated into a new act which was passed in
1748. The same author states that the next legislative body to enact a
law against rats was in Antigua in 1880. In the same article he refers
to the rat ordinance of Hongkong, adopted in 1902.

Footnote CL:

W. R. Boelter, “On Rat Laws,” Journal of Incorporated Society for
the Destruction of Vermin, October, 1908.

Private measures against rats have undoubtedly been practiced from
time immemorial. The action of Denmark, however, in passing a law for
the systematic destruction of rats and providing the organization for
that purpose is perhaps the most notable advance taken on this
subject. A copy of the Danish law appears elsewhere in this
publication.

That the citizens of other countries are equally alive to the
importance of rat extermination is shown by the fact that in England
there exists an incorporated society for the destruction of vermin,
which society in October, 1908, began the publication of a journal
which would supply trustworthy information upon the subject.

It is recognized that a detailed review of past efforts against
rodents would be unprofitable, but on account of the enormous trade
relations between important seaports it is thought that a review of
the measures taken therein against rodents would be of value.

RAT EXTERMINATION IN UNITED STATES PORTS.

Prior to the adoption of the International Sanitary Conventions of
Paris and Washington, the Federal Government had made provision in its
quarantine regulations for the prevention of the spread of plague on
ships through rodents.

The articles contained in the United States Quarantine Regulations,
issued April 1, 1903, and bearing on the subject, are as follows:

14. At ports or places where plague prevails every precaution must
be taken to prevent the vessel becoming infected through the agency
of rats, ants, flies, fleas, or other animals. At such ports or
places the vessel should not lie at a dock, or tie to the shore, or
anchor near any place where such animals may gain access to the
vessel. In case cables are led to the shore they should be freshly
tarred and provided with inverted cones or such other devices as may
prevent rats and other animals passing to the ship. The introduction
of vermin on board the vessel from lighters and all other sources
should be guarded against. In such ports sulphur fumigation should
be resorted to in the holds when empty and from time to time during
loading in order to destroy vermin.

45 (b) Free ventilation and rigorous cleanliness should be
maintained in all portions of the ship during the voyage and
measures taken to destroy rats, mice, fleas, flies, roaches,
mosquitoes, and other vermin.

45 (h) In the case of plague, special measures must be taken to
destroy rats, mice, fleas, flies, ants, and other vermin on board.

128. Vessels infected with plague, or suspected of such infection,
should be anchored at a sufficient distance from the shore or other
vessels to prevent the escape of rats by swimming.

133. Special precautions must be taken against rats, mice, ants,
flies, fleas, and other animals, on account of the danger of the
infection of the disease being spread through their agency.

134. As soon as practicable there shall be a preliminary
disinfection with sulphur dioxide for the purpose of killing rats
and vermin before further disinfecting processes are applied to the
vessel and her cargo. The killing of any escaping rats shall be
provided for by a water guard in small boats, and no person with
abrasions or open sores should be employed in the handling of the
vessel or her cargo.

135. The vessel shall be submitted to a simultaneous disinfection in
all parts with sulphur dioxide to insure the destruction of rats and
vermin. The rats shall be subsequently gathered and burned, due
precautions being taken not to touch them with the bare hands, and
the places where found disinfected with a germicidal solution; and
the quarantine officer shall assure himself that the vessel is free
of rats and vermin before granting free pratique.

Additional regulations prescribe the method of disinfection of vessels
for plague, and elsewhere in this publication is given a detailed
description of the measures taken aboard ships at Angel Island, one of
the national quarantine stations.

Elsewhere is also given an account of the measures taken to eradicate
plague from certain cities on the Pacific coast, among the measures
being the systematic destruction of rodents and practical rat
proofing.

In a letter dated November 21, 1908, requests were made to the
Department of State for reports from certain of the more important
foreign seaports as to systematic measures being practiced for the
destruction of rats. As a result much valuable information has been
received, and acknowledgments are due and here made to the consular
officers furnishing it. The data received was abstracted and
classified according to countries as follows:

RAT EXTERMINATION IN CHINESE CITIES.

Although the present pandemic of plague had its origin in Canton,
China, in 1894, and the disease has been endemic there practically
ever since, Consul-General Bergholz states that the provincial
government of Kwangtung has made no efforts to exterminate rats.

In Amoy the local authorities have never taken measures to encourage
the extermination of rats, and in the absence of assistance from the
local authorities but little can be done toward effective eradication.

An outbreak of plague in Shanghai in December, 1908, was attributed to
the introduction of rats by ships from plague-infected ports.[CM] A
plan of campaign for such an emergency had previously been formulated
and was put in operation. It included collection and laboratory
examinations of rats and organization of rat parties to destroy rats
and render houses rat proof.

Footnote CM:

The Municipal Gazette, Shanghai, January 7, 1909, Health Officer’s
report for December, 1908.

In Tientsin official efforts made to exterminate rats are on lines to
suit the convenience of the particular health official. The consulate
at that port states that generally on the appearance of plague, the
officials pay about one-half cent for each rat brought, and as the
epidemic becomes severe, as much as 2½ cents gold.

In Hongkong, the question of rats in relation to plague has been of
perennial interest. While on duty in the American consulate at that
port, my attention was forcibly called to the influence of rodents in
the transmission of plague. In 1900 it had been the practice to
encourage the destruction of rats in the city, and a reward of 2 cents
Mexican money was offered for each rat brought to the health
department. A certain number of these rats were examined from day to
day from different districts.

In August, 1901, arrangements were made by which the health department
collected and examined a specified number of rats each day to try to
determine in some degree the relative prevalence of plague among these
animals. This practice was continued for several months, with the
result that the mortality among rodents from the disease was shown to
have rapidly decreased until in November practically no
plague-infected rats were found.

In a discussion of the subject, furnished February 2, 1909, by Dr. W.
W. Pierce, medical officer of health, through Consul-General A. P.
Wilder, it is stated that in 1902 the fee for rats was raised to 5
cents, and a special staff of coolies was engaged to destroy rats. The
abuses on account of these bounties were so great, however, that it
was found necessary to discontinue it in 1903, but the method of
trapping rats was continued.

While the total number of rats taken in 1903 was 101,047, Doctor
Pierce stated in effect that on account of the prejudice against
disinfection, it was practically impossible to secure the addresses
where the infected rats were found. The services of the staff were
continued, however, until 1908, when they were abolished because it
was thought, as stated by Doctor Pierce, that results were not
commensurate with the cost, and many complaints were heard. The plan
of furnishing traps to all persons who applied was then introduced,
and in addition, structural methods which had gone on for years were
continued.

The traps were distributed through district committees consisting of
the more educated natives, who were informed that with their
assistance it would be possible to avoid abuses which had been
practiced by the official rat-catching staff.

Doctor Pierce stated that it had been impossible under other systems
to secure the addresses where infected rats were found, and in order
to overcome this prejudice, several hundred receptacles were placed in
different parts of the city whereby the rats could be collected. These
tins were visited from day to day, and by this means it was possible
to locate infected districts.

Doctor Pierce stated that the use of ordinary disinfectants in
plague-infected houses had been discontinued, and that a 2 per cent
mixture in water of a kerosene emulsion made by stirring warm tank
oil, 85 parts added gradually to 15 parts of hot, strong solution of
“sunlight” soap, was used. This solution was found to instantly kill
fleas and bugs, and it has been used systematically.

For ordinary cleansing a 1 per cent solution is used, but Doctor
Pierce stated that on the recurrence of plague special gangs would be
employed to apply a 2 per cent solution in infected localities.

Beginning with January 1, 1909, Doctor Pierce stated that a rat poison
known as “Punjaub rat exterminator” had been laid down, and that the
intensive destruction of rats by this means was under consideration.

In summarizing the measures taken against rats, the American
consul-general stated that four methods were in use, namely, rat
proofing, trapping, poisoning, and use of cats. The use of bacterial
viruses as poisons has thus far been unsatisfactory, and the use of
chemical poisons, such as phosphorus, prepared, and known as “Punjaub
rat exterminator,” has only given moderate results.

The keeping of cats is encouraged, and the consul states that some
hundreds of these animals have been imported from Macao and Canton by
the colony and distributed.

Finally, the consul states that the use of “rat funnels” has long been
compelled whenever large vessels lie at the wharves.

In Sinyang the work of exterminating rats is in charge of a physician
who has 12 assistants, which number, however, may be increased in case
of emergency. The means employed are trapping, offering rewards, and
catching by means of cats. In his report, the consul states that the
best results have been secured by trapping. For ridding houses of
rats, some use is made of fumigation. It is stated that there is not
much danger of rats invading cargo boats, but that in the country rats
are present in enormous numbers, and that the problem of their
destruction has thus far baffled all attempts at solution. Bounties at
the rate of 15 cents per hundred are paid, and in one year the
Government expended for this purpose $32,500.

RAT EXTERMINATION IN MADRAS, BOMBAY, AND CALCUTTA, INDIA.

In Madras, Consul N. B. Stewart states there is no legal enactment in
effect requiring the destruction of rats, but the Government has done
everything in its power to make the public understand the value of
such a measure as a preventive against plague. In 1907 a reward of
one-half anna, equal to 1 cent, was offered by the city for each large
rat killed, and one-fourth anna for each small one. Bounties of
one-fourth anna and one-twelfth anna each for the respective varieties
of rats were still being continued at the time report was made.

In Bombay, where plague has been endemic since 1896, destruction of
rats and examination of all dead rats and evacuation of rat-infected
areas are included among the measures taken by the health department
in connection with plague operations. In his report Consul E. H.
Dennison states that the present antirat campaign in Bombay includes
the distribution of poisons, the trapping of rats, and the reward of 1
cent for each live rat, and a half cent for each dead rat, delivered
to the health department. He also states that there are no by-laws or
acts under which the destruction of rats can be enforced in private
houses.

On account of religious opposition, and to teach the people,
educational posters signed by the health officer were displayed,
containing advice what to do to prevent plague, which in part reads as
follows:

1. Beware of rats in your dwelling houses.

2. To harbor rats is to court plague.

3. Rat infection and consequent rat mortality are the indications of
the impending plague visitation among human beings.

4. Allow the health department staff to place rat traps in and about
your houses to catch rats and take them back.

5. Freedom from plague is in the removal of rats.

6. Inform the health department when dead rats are found in or near
your houses.

7. Clear your houses of all materials likely to harbor rats.

The same placard also contains information regarding disinfection to
kill fleas, evacuation of infected areas, and inoculations to produce
immunity.

In a special report dated January 23 the consul described a new
experiment in rat destruction; that is, an intensive effort in the
Kamatipura district. The district was divided into divisions and
subdivisions in which simultaneously there were distributed for use on
a certain day 19,642 poison baits and 2,670 traps. It was stated that
as a result hundreds of rats were collected the following morning.

No reference is made to measures taken for the destruction of rats
aboard ships in the harbor.

In Calcutta, it is reported by Consul-General W. H. Michael that
various methods are resorted to for the extermination of plague, rats,
the use of poison being the most general. Rewards have been offered
for live and dead rats, and about 11,135 dead rats were produced, but
it was found that a considerable portion of these was picked up by
conservancy coolies, and the reward for dead rats was therefore
discontinued. Of live rats, only 9,447 were produced. After December
1, 1908, the reward was raised to 4 cents, with the result that 49,396
live rats were captured. It is stated, however, that this did not seem
to have any appreciable effect upon the rat population.

RAT EXTERMINATION IN YOKOHAMA AND NAGASAKI, JAPAN.

In the Kanagawa Ken, in which Yokohama is located, the following
ordinances relating to the extermination of rats have been enacted:

_Kanagawa Ken Ordinance No. 64 of 1902 (issued October 8)._

Finders of dead rats within the prefecture shall immediately report
and deliver same to the nearest police, village, or other
authorities in charge. Upon receipt thereof, the police or other
authorities shall without delay transmit the same to the police
headquarters (Yokohama).

_Kanagawa Ken Ordinance No. 45 of 1903 (issued June 26)._

Finders of a dead rat or capturers of a live rat shall report and
deliver the same within twelve hours to the police, mayor, medical
inspector or officer, antiplague committee, or officer in charge of
the Hygiene Guild.

Violation of the foregoing shall be punishable either by a fine or
detention in jail.

_Kanagawa Ken Ordinance No. 63 of 1907 (issued June 8)._

Persons who plan or are engaged in the importation of rats from
without into the city of Yokohama, or persons who plan to breed rats
in the said city, shall be punished by detention in jail or by a
fine.

_Extract from Kanagawa Ken Ordinance No. 14 of 1907, relating to
supervision over storage and warehouses (issued March 6)._

ARTICLE 1. The term “storage and warehouses,” hereinafter mentioned,
shall mean and include any godown, storage or storehouses, or
warehouses, used by storage or warehouse companies, individuals,
forwarding agents or express companies, wholesale dealers, works and
factories, wherein cotton, cereals, or grains, flour, peanuts,
beancake, and other pressed oil cakes, cocoons, feathers, leather,
old or waste cotton, old straw, bags, etc., are stored and kept.

ART. 8, sec. 1. Owners of a storage or warehouse shall exercise at
least four times a year a rigid and thorough method of house
cleaning and rat destruction in the storage or warehouse. The date
and time of cleaning shall be reported to the police, to whose
satisfaction and approval the cleaning must be carried out.

ART. 8, sec. 2. Owners of a storage or warehouse shall furnish and
always keep at each doorway a suitable rat trap, and shall always
endeavor to exterminate rats or pursue such method of extermination
as may be directed by the police.

In forwarding the above ordinances, Vice-Consul Babbit stated that
vessels engaged in foreign trade, when deemed advisable by the harbor
authorities, are required to endeavor to exterminate the rats on board
by sulphur fumigation or other effective methods, as are also
coastwise vessels.

To encourage the extermination of rats, the mayor of Yokohama was
authorized by the city council to pay bounties, the rate being 3 sen
(1½ cents) each. The vice-consul states that in addition to this
purchase price a ticket is given for a lottery, and for each 60,000
rats 156 prizes, amounting to a total of 1,000 yens are given by the
city.

In a table giving the number of rats purchased and sent to the hygiene
bureau for bacteriological examination, it is seen that for the year
ending December 31, 1908, 447,981 were received.

In Nagasaki the municipal council passed an ordinance January 6, 1906,
as follows:

1. Rats to be purchased are of two kinds—house and field rats—and
they must be either caught or found dead within this city.

2. A bounty of 3 sen (1½ cents) shall be paid for each rat with a
ticket, to be cashed on presentation.

3. Such tickets, to be cashed, must be presented at the city office
within thirty days from the date of issue.

4. Rats shall be purchased at the city office, police stations,
branch police stations, police boxes, or by city officials, who go
around for such purpose, by giving a ticket to be cashed upon
presentation, provided that distinction must be made between a rat
caught and one found dead.

In transmitting a copy of this ordinance Consul G. H. Scidmore stated
that it was issued in accordance with the infectious diseases law of
Japan, No. 36, of March, 1897, which provides that cities, towns, and
villages shall make all necessary arrangements relating to the
extermination of rats as may be ordered by the prefectural governors.

He also stated that when the above ordinance was decreed the mayor of
Nagasaki issued detailed instructions regarding its enforcement. The
ordinance was enforced from the time of its enactment until July 7,
1908, when the city ceased paying bounties; from January 13, 1908, to
July 7, 1908, 980.33 yen ($488.20) having been expended, and 30,767
rats having been destroyed.

RAT EXTERMINATION IN LOURENÇO MARQUEZ, EAST AFRICA, AND MADAGASCAR.

In Lourenço Marquez, Consul W. S. Hollis states that a disinfecting
barge is maintained, and requisitioned from time to time by vessels,
by which means considerable numbers of rats are destroyed.

He also states that the last efforts to destroy rats on shore were
made during the plague outbreak in November and December, 1907.

In a circular accompanying Provincial Decree No. 754 of the
governor-general, the following relates to the destruction of rats:

1. For the destruction of rats we advise the public to make use of
poison paste.

2. These may be obtained by requisition on the municipal chamber and
from police stations.

3. The paste furnished shall be divided into portions and
distributed in different parts of the dwellings.

In Provincial Decree No. 737, issued December 11, 1907, by the
governor-general, it is required that grain and forage warehouses and
stables be provided with cement floors, and that ventilators be
provided with wire screens sufficiently fine to prevent the access of
rats, and that interior doors and salient angles be provided with
metallic points to prevent the climbing and entrance of rats.[CN]

Footnote CN:

Cases of pest in Lourenço Marquez, official report.