the buildings which have high walls or in dark rooms is a much
more difficult proposition than their destruction in low tents,
where all can easily be seen and reached. It would be a large
advantage to have the interior of buildings painted a light colour
or white- washed so that Anopheles could be readily seen when
resting on the walls. We now use test-tubes containing cotton
wool and chloroform to destroy adults resting on walls, etc. It
is quieter than the slapping method, and very few mosquitos
are frightened away.

At the base of Diablo Hill is a swampy area about two miles
long and a half a mile wide. It cannot be drained at the present
time. From the top of the hill to the water-line is about 200
yards. In June of 1908 several hundred United States Marines
were stationed at Camp Diablo, and remained on this hill for
about six or eight weeks. The conditions affecting malaria,
such as drainage, etc., were then the same as they are to-day.
While the Marines were in the camp their malarial sick-rate



362 ANTI-MALARIAL WORK ON ISTHMUS OF PANAMA [Sect.

was 2^ per day, or 14% per week. Since that time a string of
railroad cars in which the labourers of the railroad construction
gang sleep was located near the foot of the hill, and between
the swarap and the camp formerly occupied by the Marines.
During the past thirty weeks an average of forty-four Anopheles
per day have been destroyed each morning in these cars. They
were caught in chloroform tubes as above described. It takes
the labourer thirty minutes each morning to do this work. The
cost is 5 cents per day, or 30 cents per week, and the destruc-
tion is carefully performed by a competent man. From the
first week in May 1909 to 30th November 1909, which is the
rainy season, only four cases of malaria have occurred among
the forty labourers sleeping in these cars, or about one man in
300 men working for a period of seven days, although they were
more freely exposed to the Anopheles than the Marines had been.
This work of destruction of adults in quarters costs so little
that undoubtedly it will be of value in all malarial districts
where house tenants are interested in the prevention of malaria.
It will be of special importance where an army is in camp, or
where railroad camps are established in malarial districts, as
with proper care the sick-rate could by this means be kept far
below what it would otherwise be. On the Isthmus we consider
such work as supplementary to the drainage and other anti-
malarial measures.

It should be noted that most of the labourers' camps in the
Canal Zone are located near native towns, and undoubtedly
a large percentage of what malaria we do have is contracted
by our labourers spending their evenings at, or living at the
native settlements. Nevertheless, in spite of continuous topo-
graphical changes, constant rains, native villages and numerous
other difficulties, the malarial sick-rate is being steadily and
systematically decreased year after year. The decrease of adult
Anopheles to be found at the camps is equally noticeable.

Several years ago it appeared that the malarial sick-rate
would always be much higher during the rainy season than in



43] RESULTS AT HAVANA 363

the dry season, but during the past two years the Department
of Sanitation have been able to control the situation to such an
extent that at some of the larger settlements there has been no
appreciable increase in the number of malarial cases during the
wet season as compared with the dry season. It is of interest
to note that this has occurred in those districts where during
previous years the increase of malaria closely followed the
increase of rainfall. This is very encouraging, considering that
such results have been obtained where the settlements are
scattered over large areas.

With regard to the destruction of adult Anopheles in dwell-
ings it should be stated that malaria cannot always be controlled
by this means only, although it was fairly successful at Diablo
and Cocoli. The colour of the house walls, height of the ceiling,
the amount of light in rooms and the number of hiding-places,
etc., effect the percentage of adults that may be destroyed.
Again, if persons living in houses that are inspected daily visit
houses that are not so treated, or are infected elsewhere, the
results will not be as satisfactory as where their camp is iso-
lated as was the case at Cocoli and at Diablo. Drainage and
eradication of breeding-areas is the all-important work in an
anti - malarial campaign. The catching of adults should be
considered as supplementary to drainage, screening, application
of larvicide, etc. At Havana we relied exclusively on drainage
and filling. Most of the natives there do not like to take
quinine. Malaria at Havana has practically been eradicated.

Data relating to charts showing reduction of malaria in the
Canal Zone. — Chart No. i shows the percentage of all Canal
employees (malarial cases only) that were sent to the hospital
each month from 1906 to 1909 inclusive. Attention is invited
to the fact that the sick-rate is always lowest about May or
at the end of the dry season. That the malarial sick - rate
would advance rapidly in former years with the arrival of the
wet season June, July and August. This advance has been
materially checked. Compare the wet season record of 1909
(June to December) with the same period of the previous years



364 ANTI-MALARIAL WORK ON ISTHMUS OF PANAMA [Sect.

and with the dry season of 1909 (January to May). The
successive yearly reductions are a fair index of the value of the
anti-malarial work.

The successive months are plotted one half inch apart,
horizontal measurement.^ The percentage malarial sick-rate is
plotted on the vertical lines, on a scale of two inches vertical
measurement, equals i^. If the force employed consisted of
40,000 men, and 500 of them are sent to the hospital with
malaria during a month, then the rate on Chart No. i for that
month would be plotted as r25^.

Chart No. 2 is a record of malarial cases among employees
at Porto Bello. The percentage sick-rate for each week plotted.
This was a new camp that was opened up a few weeks before
anti-malarial work started. At all newly opened camps the
malarial rate runs high, as compared with areas where anti-
malarial work is being done. Without doubt the rate would
remain high if no anti-malarial work were done. Note that
preventive work at Porto Bello started 21st March 1908, and
that the rate from then to June averaged, say, about 3^ per
week. Or, over 12^ of employees were sent to hospital per
month (malarial cases), and many of the labourers remaining
at work were not in physical condition to do as much work as
they are capable of doing to-day. That during this same
period, among employees in the Canal Zone, the monthly sick-
rate (malaria only) was not much over i^. (See Chart No. i.)
About 600 men are located at Porto Bello,

Chart No. 3 is a record of malaria at Gorgona. Present
population 2,000 employees. Compare years 1908 and 1909
with the previous years. No large increase of malaria occurs in
the wet season (June to December) during the last two years.
Anopheles are now seldom found in barracks, which indicates
that they are not numerous. Note the effect of the wet season
on the malaria rate for 1906, and absence of same for wet
seasons of 1908 and 1909.

In Charts No. 2 and No. 3 the weekly sick-rates are given.
^ The accompanying charts are reduced. — R. Ross.



43] RESULTS AT PANAMA 365

For instance, during the week ending 6th January 1906 a
number of the employees at Gorgona (Chart No. 3) were sent
to the hospital whose cases were diagnosed as malaria. This
number consisted of 274^ of the entire working force living
at Gorgona during that week. The dates of the ending of
each week for which the percentage sick-rate is plotted are
given. These percentages show only the malarial sick-rates
and not the other hospital cases.

In connection with Chart No. i it should be stated that in
the early days it was difficult to get the malarial patients from
among the ignorant labourers to go to the hospital, and so the
actual sick-rate at that time was higher than what has been
recorded. At the present time the labourers go voluntarily to
the hospital when they feel sick. Note that during seven
months of 1906 the rate was above 6%; that during 1907, for
ten months, the rate was below 5%. In 1908, during eleven
months, the rate was below 4%. In 1909, the rate was below
3%. The highest monthly rate during the wet season of 1909
was a little over 2//, as compared with 4%, 5% and 10%
respectively for the wet season of the years 1908, 1907 and 1906.

Refer again to Chart No. 2, relating to malaria at Porto
Bello. During December of 1909 the number of rainy days
was twenty-seven out of thirty-one. The rainfall was 45*03
inches for November and 58'i7 inches for December 1909, as
against 4173 and 2572 inches respectively for November and
December of 1908. Such conditions of rainfall mean a large
increase in the number of possible Anopheles areas. As shown
on the chart, no increase of malaria occurred due to the
increased wet area accessible to Anopheles.

This is a good illustration of the results of anti-malarial
work performed under severe conditions when the work might
at first sight appear to be almost impossible to accomplish.
From 1st November 1908 to 2nd January 1909, 5% of the force
were sent to hospital with malaria. From 31st October 1909
to 1st January 19 10, during the period of heavier rainfall, only
3'26% of the force were hospital malaria cases.




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By Sir RUBERT BOYCE, F.R.S.

Professor of Pathology, University of Liverpool

44. Malaria in the West Indies. — There is no doubt that
malaria has markedly decreased throughout the West Indies.
This statement can be verified by comparing the current health
reports with those furnished by the Surgeon-Generals when
the various islands were garrisoned. The factors which have
brought about this diminution are the same as those which
have, in more recent time, operated in towns like Bombay,
New Orleans, Rio, etc., and which at a still earlier period
led to the disappearance of malaria from a large portion of
Europe.

It may now be stated that malaria as an endemic disease
is limited to the country districts throughout the islands, and
that it ceases at the outskirts of the principal towns, in a few
instances penetrating into a centre of population along the
banks of some neglected marsh or stream.

In the principal towns the swampy ground which almost
invariably surrounded the early settlements has now all been
reclaimed, and in its place well-planned streets have appeared.
Properly-graded roads and concrete drains are the rule rather
than the exception. Since the year 1850 a considerable pro-
portion of the larger towns received the immense advantages
of a pipe-borne water-supply, derived from reservoirs or rivers
outside the towns. This system at once did away with the
old-time wells, and abolished, or greatly decreased, rain-water
barrels and storage tanks. These improvements, coincident

369 2 A



370 MALARIA IN THE WEST INDIES [Sect.

with the progress of prosperity and the appreciation of the
laws of hygiene, have together brought about the cessation
of malaria and yellow fever as endemic diseases in the chief
towns. Therefore it is to the country districts, and on the
plantations, that the student must look for the survival of
malaria in its endemic form. And there is no doubt that it
does still so survive throughout the Antilles, as an analysis
of the Registrar-General's or the Medical Officer's Mortality
Returns abundantly proves. Unfortunately, it is very difficult
to estimate accurately the total sickness and mortality rates
from malaria in the various islands ; in many instances the causes
of death in 50^ or more of the cases is not definitely stated.
And, of course, as is well known, although the anaemia of
malaria may have had the chief share in producing lowered
vitality, yet the actual cause of death is registered as perhaps
bronchitis or consumption, as the symptoms of these affections
were the more obvious ones from which the patients suffered
during illness.

Efforts are now being made, however, to make more accurate
estimates of malaria by the employment of more perfect methods
of diagnosis, such as spleen rates and blood examinations.

Grenada. — Population, 68,253. Capital, St George's ; popula-
tion, 5,198.

Malaria is still prevalent in the country districts, and is
endemic and imported. In No. i District in St George's Parish
681 cases and 22 deaths were recorded in 1906, and 317 cases
and 12 deaths in 1907. In No. 6 District 1,119 cases were
reported in the same year. The malaria is due to the breeding
of Anophelines in certain swampy lands and puddles, and, in
the wet season, perhaps also to the presence of water-holding
epiphytes upon the shade trees on the cocoa plantations.

Preventive Measures : —
I. Introduction of pipe-borne water. This was the first step
which led to the reduction of Anophelines in the



44] GRENADA, ST VINCENT 371

towns of St George's, Gouyave and Grenville by doing
away with numerous barrels and odd water containers.

2. Road-making and street drainage in the towns.

3. Government and medical officers throughout the colony

making returns of all anti-malarial measures under-
taken in their respective districts.

4. 1st April 1909. — The fish " millions " were introduced into

the colony with the object of stocking ponds and
large collections of water.

5. The Public Health Ordinance of 1907 prohibited the

keeping of stagnant water unless protected, oiled
or stocked with fish, and all odd receptacles were
to be removed.

6. In 1902 and 1905 further ordinances were promulgated,

declaring mosquito breeding - places in and about
human habitations to be a statutory nuisance.

7. The more careful cultivation on the cocoa estates has

led to better drainage, and a diminution of malaria
on the estates.

8. Considerable attention is now paid to entomology.

St Vincent. — Population, 47,548. Capital, Kingstown ;
population, 4,547.

Malaria for the most part confined to small, swampy districts
in the country. The Medical Officer's returns show 525 cases
in 1907, and 281 cases in 1908.

Prophylaxis : —

1. Pipe-borne water has led to great diminution of water

barrels and odd receptacles and wells.

2. Construction of side drains and roads.

3. Removal of odd receptacles from yards, and better

sanitary supervision.

4. A nti-larval meastires —

1901. — Measures promulgated against stagnant water, unless
oiled, screened or stocked with fish.



372 MALARIA IN THE WEST INDIES [Sect.

igoQ. — New Public Health Ordinance, with provision
against stagnant water and mosquito larvae.
5. The late Dr Branch was a keen entomologist, and did
much to get rid of breeding-grounds of mosquitos.

Sf Lucia. — Population, 50,000. Capital, Castries.
There is still a small amount of malaria, due to a few low-
lying, swampy patches which persist near Castries.
Prophylaxis : —

1. Introduction of pipe-borne water brought about a great

reduction in the number of breeding-places.

2. Better roads and side drainage undertaken from 1890-

1900.

3. Energetic anti-mosquito drainage and bush clearing

operations undertaken by Major Hodder.

4. Anti-mosquito laws. — In 1906 the Colonial Secretary

commenced a vigorous systematic campaign against

mosquitos, by causing careful returns to be made of

all insect -carried diseases and of the breeding-places

of mosquitos.
In 1907 regulations were framed dealing with stagnant

and waste water.
In 1909 a vigorous house-to-house campaign amongst

mosquitos was started.
Fines have been regularly enforced from 1907 against

all who, after caution, refuse to get rid of mosquito

larvae.

Trinidad. — Population, 336,769. Chief Town, Port of Spain ;
population, 70,000.

General death-rate for 1908, 10 per milk.

Total deaths from malaria, 71 in 1908. Total amount of
malaria small.

Upon the estates, however, malaria is responsible for more
than half of the gross sickness rate amongst the indentured
labourers.



44] TRINIDAD, BRITISH GUIANA 373

Prophylaxis : —

1. Pipe-borne water-supply. — This system was first intro-

duced into the Port of Spain as far back as 185 1,
and has since then been largely extended throughout
the Port of Spain. To it must be ascribed the
abolition of endemic yellow and malarial fevers,
for it at once did away with the necessity of the
numerous water barrels, cisterns, wells and odd
receptacles of all descriptions, which in the old
days were the breeding-places of the mosquitos.

2. The construction of well - graded roads and concrete

drains everywhere within the vicinity of the town.

3. Concreting backyards, removal of rubbish and bush.

4. Education. — Systematic training of the sanitary

inspectors, schoolmasters and others throughout
the colony.

5. Entomology. — The establishment of a strong entomo-

logical department to study the breeding-places of
mosquitos.

6. Anti - larval laws. — In 1907 regulations were made

against stagnant water and larvae, enforcing the
screening or oiling or fish stocking of stagnant
water which could not be got rid of
In 1909 a new Draft Ordinance was prepared strengthen-
ing these regulations, and numerous fines have been
inflicted for contravention of the Mosquito Bye-laws.

British Guiana. — Population, 278,328. Capital, George Town.
Colony intersected by innumerable water trenches, swamps
and canals.

Malaria, the principal disease of the colony.
In 1907 the deaths from malaria were 301.
Prophylaxis : —

1. Construction of good roads and drains.

2. Pipe-borne water-supply to George Town not completed.

3. Fish stocking of all waterways.



374 MALARIA IN THE WEST INDIES [Sect.

4. Education, and training of sanitary inspectors, teachers,

schools, etc.

5. Sanitary supervision, removal of odd water receptacles.

6. Drainage Ordinance. — In 1907 Bye-laws were intro-

duced enforcing proper drainage in George Town ;
later these were extended to the country districts.
Vat Screening. — In 1907 an Ordinance was introduced
to render compulsory the screening of vats, and this
law was enforced in 1909.

7. The distribution of quinine.

Barbados. — Population, 199,542. Chief town, Bridgetown.

It is stated on good authority that there are no Anophelines
present in this island.

Malaria is not endemic ; imported cases of malaria are
common amongst the labourers returning from Panama. The
absence of Anophelines is attributed to the very porous nature
of the soil throughout the island, which prevents the formation
of puddles. The ponds which are met with are all apparently
stocked with " millions."

In Bridgetown the streets are well drained and kept flushed.

Water-supply. — An abundant and excellent pipe-borne
water-supply was introduced into the colony many years ago,
and has since been extended. It strikes at the root of endemic
yellow fever by putting an end to the innumerable odd water
receptacles which were everywhere abundant.

In 1909 a vigorous anti-mosquito compaign was started,
and the Anti-stagnant Water Ordinance of 1909 was rigorously
enforced.

Sanitary inspection was increased, and a general cleansing
and removal of all odd water receptacles carried out.

The Bahamas. — In 1905 measures were adopted against
mosquito-carried diseases, and in 1907 anti-larval regulations
were enacted, and screening, oiling or fish stocking of stagnant
water enforced. Quinine was also distributed.



44] JAMAICA, BRITISH HONDURAS 375

The Northern Islands. — In 1904 vigorous action was com-
menced against mosquitos.

Jamaica. — Population, 639,491. Capital, Kingstown.

Anti-malarial measures in Jamaica. — In October 1909 a
special commission was appointed to investigate and to take
measures to remedy the conditions which gave rise to malarial
fever in different parts of the island of Jamaica. The Com-
mission consisted of the Colonial Secretary, P. C. Cork, Arch-
bishop Nuttall, the Superintending Medical Officer, Dr Kerr,
Dr Turton and Dr Graham, and Messrs Gideon and Hart.
Mr Isaacs was made Official Secretary of the Commission.

The objects of the Commission were to ascertain the breed-
ing-places of Anophelines, and to suggest the carrying out of
remedial and preventive measures ; also to conduct investiga-
tions and to take evidence if necessary. The Commission had
power to expend up to ;^500.

British Honduras. — Chief town, Belize ; country very
swampy.

Prophylaxis : —

1. Anti-mosquito work was commenced in 1905, and has

been kept up with marked success.

2. A mosquito destruction Ordinance was passed in 1906.

Owners of property were compelled to screen, oil
or stock with fish all collections of water.

3. Drainage and filling - in operations have also been

started.
Bush clearing was enforced.



By W. T. PROUT, M.B., C.M.G.

Lately P.M.O. Sierra Leone

45. Malaria in Jamaica.— The chief factors which influence
the prevalence and distribution of malaria in Jamaica are, first,
the physical configuration of the island, and second, the methods
of cultivation, which are necessitated by the requirements of its
forms of agriculture.

The centre of the island is occupied by a lofty chain of
mountains trending generally east and west, from which spurs
are thrown off running north and south, with intermediate fertile
valleys : while the coast is occupied by flat alluvial land of vary-
ing extent. From the mountains a number of streams, some of
considerable size, rush precipitously down till they reach the
lower plains, where they frequently form extensive grass-grown
swamps and open into the sea by a series of shallow, sluggish
mouths, in all of which malaria-carrying mosquitos breed in
great abundance.

Moreover, it is naturally in the alluvial plains that the staple
industries of the island, namely, banana and sugar plantations,
are carried on. In the north-eastern portion, where the land is
almost entirely under banana cultivation, there is a heavy rain-
fall, and the soil is stiff" and clayey. In consequence, the banana



Sect. 45] MORTALITY AND MORBIDITY 377

plantations have to be deeply trenched for the purpose of subsoil
drainage, and the trenches, unless properly graded and kept
clear of grass and weeds, afford suitable breeding-grounds for
Anophelines.

In the south and south-eastern parts of the island different
conditions obtain. The rainfall is small, and irrigation, both on
banana and sugar estates, is imperative. Here again the canals,
unless properly supervised, are a prolific source of mosquitos.

Among minor factors may be mentioned the ponds formed
by surface drainage, invariably grass-grown, and used sometimes
as the water-supply of a village, and more frequently as cattle
ponds ; and the shallow, earthen, weed-covered gutters along the
sides of the streets of the villages and towns.

General malarial death- and sick-rates. — Although the exten-
sive prevalence of malaria in certain districts of Jamaica has
long been recognised, and its seriousness as affecting not only
the general health and the death-rate of the community, but
the agricultural development of the colony, was fully appreci-
ated by the medical profession, yet, apparently from the apathy
of the laity, no attempt appears to have been made to make an
accurate malarial survey of the island, and preventive measures
were practically non-existent. In the latter part of 1908, how-
ever, an expedition from the School of Tropical Medicine of
Liverpool visited the island, and, thanks to the active co-opera-
tion of the Government and of the Island Medical Service, a
systematic though limited survey was made, and much useful
information was obtained. The following statistics are mainly
taken from one of the reports of the expedition by myself
{Ann. Trop. Med. Ill,, No. 4, 17th November 1909).

The total malarial deaths for the whole island for a period of
ten years amounted to 34,695, which is equivalent to a malarial
death-rate of 4*4 per 1,000. The general death-rate during the