opposed to the seventh sanitary axiom given above. Although
it possesses what some governments may consider to be an
advantage, namely, that it does not make direct demands upon
their own finances, it may yet be in the end more costly to the
public than other measures. In most countries the number of
houses is equal to about 1/4 or 1/5 of the total population — that
is to say, the houses are very numerous. The cost of screening
each house or of providing all the innates with mosquito-nets
will therefore mount up to a very large sum. Thus in a city
300 PREVENTION [Sect.
of 30,000 inhabitants, there are hkely to be 6,000 houses, and if
the average cost of screening each house amounts to only £1,
the total cost, including that of maintenance, will be very large.
I doubt whether any form of screening for the poor will not
depreciate at the rate of 50% per annum. It may therefore
happen that the total cost will greatly exceed that of mosquito
reduction or treatment. Even if it does not exceed that of
mosquito reduction, the advantages of the latter are so great
that it would be preferable to adopt it (if it is feasible).
So much for protection as a general measure ; but it is often
decidedly called for under special circumstances, as for isolated
houses in the country, especially in proximity to marshes ; and
for hospitals, barracks, prisons, hotels, travellers' rest-houses,
tents, ships, river-boats, and so on.
For general prophylaxis, especially in crowded localities,
Anopheline reduction has many great advantages, which I have
often pointed out. Practically, Anopheline reduction may be
generally merged into the wider measure of mosquito reduction,
which costs little more to effect and adds greatly to the benefits
obtained. It is essentially the radical measure, which tends to
remove not only the carriers of the disease but also a continual
source of annoyance to the public. As mosquitos are known to
carry other diseases, namely, yellow fever, filariasis, and almost
certainly dengue, mosquito reduction will probably do much
more even than to reduce malaria. To the practical hygienist
it has still greater claims for consideration, especially because it
conforms perfectly, not only with the eighth sanitary axiom,
but also with the sixth and seventh — which is not the case with
some of the other measures. For example, a government or
municipality can maintain men for the purpose of removing
breeding - places without causing any trouble at all to the
populace. A certain amount of legislation is required to
control obstinate people who sometimes refuse out of wilfulness
to allow sanitary agents into their premises ; but beyond this
it is generally advisable for the authorities to do everything as
39] MOSQUITO REDUCTION 301
regards mosquito reduction for themselves. No one is asked to
believe in the mosquito theory, or to take drugs, or to protect
himself and his family with bed-nets, or to put screens to his
windows. Nor does mosquito reduction cause much or any
inconvenience to the public (axiom 6). Occasionally cultivation
in proximity to towns must be controlled, and pits, cisterns,
wells, etc., used for irrigation must be dealt with ; but compensa-
tion for any harm done must be paid for by the authorities,
and, where mosquito reduction is generally feasible, only a
small proportion of the people are affected in such matters.
Lastly, mosquito reduction has the advantage (which is not
always recognised) that it compels the sanitary authorities
always to maintain a minute inspection of the area under their
care, compels cleaning of all premises, removal of waste water,
proper maintenance of roads, and so on (section 35).
Practically, however, questions of cost and feasibility have
to be considered. It is almost impossible to give an estimate
of the cost of mosquito reduction, which may depend every-
where on the nature of the soil, the slope of the ground, the
rainfall, the vegetation, the existence of marshes, the character
of the drainage and of the sanitary department already in use,
and so on. Quite possibly, although the necessary expenditure
is really within the capacity of the local budget, the authorities
may not think so at the moment, so that the health officer
is left powerless to adopt this measure. The advantage of
mosquito reduction, that it can be carried out entirely by the
state, has a corresponding disadvantage, namely, that the state
imagines that it alone pays for the work. In a perfect govern-
mental machine, the state could immediately call for increased
taxes in consequence of any work of absolute public necessity ;
but in this very imperfect world, the public is apt to be rather
blind in these matters, and the state is afraid of arousing
hostility, even by saving people's lives. At the same time it is
proper to note over and over again that mosquito reduction
often really does not cost as much as some pretend. The
302 PREVENTION [Sect.
figures for Ismailia and the Federated Malay States include
large items in excess of the actual anti-mosquito campaign, that
is, items for general drainage, for building sites or cultivation
purposes ; and those for Panama are so mixed that wc cannot
exactly extricate the cost of this measure by itself^ Moreover,
by the general principles of section 28, malaria may be com-
pletely reduced even by a partial reduction of the Anophelines
below the necessary limit (which I have roughly estimated to
be about 40 different Anophelines per head per month) ; and it
may be partially reduced even by a smaller reduction of the
insects. In fact the small measures under the head of minor
works generally cost but very little, and though they may not
suffice for complete mosquito reduction, are still likely to do
much good, especially if combined with other precautions.
Prevention by treatment also has many advantages. In
every locality, even if every mosquito can be banished, a
number of cases are likely to continue to suffer from relapses
for many months, and these always require careful treatment.
Hence case reduction should always be adopted as much as
possible, whether the other measures are used or not. Such
case reduction can hardly come within the sixth and seventh
sanitary axiom, because no inconvenience or trouble is inflicted
on the people by gratuitous treatment of their sickness.
Another great advantage is that the measure can be com-
menced, even on a somewhat large scale, by medical men,
without making any immediate large demands on the public
purse. As shown in Italy and Greece, the mere sale of quinine
at cost price by Government produces an excellent effect, if the
people are intelligent enough to use it. Moreover, medical
men who are now best acquainted with the whole theory of
malaria, are precisely those who carry out this measure. In
fact their practice actually receives some benefit by it, at least
at first ; they are accustomed to the use of drugs, and they find
no difficulty in urging their patients to take quinine.
' Col. Gorgas says $2"o a head (secLion 42).
39] BY TREATMENT 303
Unfortunately, all this does not apply in many countries
in which the number of qualified medical men is very small.
In many other countries the natives object entirely to our forms
of treatment, and rebel even against quinine. Still further,
many people are afraid of admitting the existence of domestic
illness amongst their children, or will not take the trouble to
treat them at all. Others, again, refuse to buy quinine, even
at the cheapest rates, or cannot afford the time to attend
hospitals or dispensaries for it, so that inefficient doses are
frequently taken, with the result that the patients become
sceptics as to the value of the drug, and advise their friends
against it. In fact, these practical difficulties are so great that,
as I stated in my Mauritius report, we are obliged in the tropics
to distribute the drug gratis from house to house if we wish to
obtain any material benefit from it. Lastly, if we propose to
confine ourselves only to case reduction, that is, to the treatment
of the sick, we have to distinguish the sick from the healthy,
which generally can be done only by medical men, or by
qualified assistants at the cost of considerable and continued
labour.
This trouble is saved if the public can be persuaded to
adopt not only case reduction, but also quinine prophylaxis —
that is, the treatment of persons who have not yet shown
signs of illness, but may possibly have become infected.
Unfortunately, if there are difficulties in the way of treating
the sick, there are sure to be still greater difficulties in the
way of persuading healthy persons to take any form of quinine
continuously. Poor and ignorant natives, and indeed many other
people, object strongly to this course. Some say that they would
actually prefer the occasional chance of malaria to a continued
certainty of dyspepsia. It is true that if quinine is given daily
in small doses it produces much less physiological effect ; but
in the majority of persons it always does produce some slight
inconvenience. Busy people, hard-worked labourers or mothers
of families tend to rebel very much against any continued
304 PREVENTION [Sfxt.
medication. We know in Europe how much people are apt
to protest against vaccination — a single simple operation causing
scarcely any discomfort, and protecting for years against a
dangerous and disfiguring disease ; how much more, therefore,
will people be apt to protest against a medicine which must
be taken daily for months during the malaria season, even
if they are not affected by the disease. Of course, persons
who remain infected, specially children, always continue to be
a danger to their neighbours, and for this reason alone a
complete reduction of malaria by treatment must always be
difficult, unless the authorities have such power that they can
actually force the drug down the throats of the people. This
is often possible in the case of soldiers, employees of companies,
or coolies on plantations, but scarcely for the general public.
On the other hand, we may rest assured, though complete
case reduction is seldom practicable, that the partial measure
is certain to do much good. Because we cannot force all the
people to take quinine, that is no reason why we should not
persuade as many as possible to do so.
Segregation, either from marshes or from infected persons,
should not be looked upon as a measure of general public
prevention, as it is applicable only in a few cases.
Next, let us compare the measures two and two — at the
risk of repetition. First, suppose that we have to deal with
an ideal country where all the measures are equally feasible,
and will cost the same sum of money — a thing which, of course,
never happens.
Protection is evidently at a disadvantage compared with
mosquito reduction. It will never entirely prevent the bites
of mosquitos ; nets and screens always require some trouble
to keep in order, and certainly add somewhat to the heat-
often so unbearable in the tropics. On the other hand, mosquito
reduction, if sufficient, removes at once an incubus, a veritable
plague — we breathe, move and sleep freely, our children are
safe, our verandas and gardens open to us.
39] COMPARISONS 305
Now, compare protection with prevention by quinine. The
former guards us not only against all mosquito-borne diseases,
but against constant personal annoyance ; the latter, only against
malaria. Nets and screens cause no dyspepsia, no ringing in
the ears, and no daily trouble with the children. I think that
every one will prefer freedom both from mosquitos and from
dyspepsia to the inflictions of both. Hence protection has
great advantages. But, in spite of this, the sick must still
be treated.
Mosquito reduction has all the advantages of protection
and more, and is therefore greatly preferable (under our
hypothetical conditions) to quinine. But, nevertheless, the
sick must still be treated.
Ideally, therefore, mosquito reduction is by far the best
measure. Protection is next, and quinine last.
Now, let us consider the measure from the point of view
of cost and feasibility. The cost of protection must obviously
vary according to the number of houses, which can be roughly
ascertained by dividing the population by about four or five.
In Mauritius at the census of 1901 the population was 373,336,
and there were 93,031 houses, so that there were about 4*25
persons to each house on the average. Probably the cost of
protecting a single house there would be quite £1 on the
average, as a very low estimate, amounting to ^^93,031 (about
1,500,000 rupees) for the whole island. Besides this, repairs
and renewals of the screens and nets would probably amount
to quite 2$/^ of the original cost at a low estimate; so that
after the first installation of the protection an annual cost of
;^23,ooo (350,000 rupees) would have to be incurred for the
mechanical work of supervision. This, of course, is a very
rough estimate, and quite possibly more than £1 would be
required to protect each house on the average, because many
of the poorest houses are little better than shelters of mud and
thatch. Regarding the feasibility of protection, I repeat that
it cannot be forced by Government on the people except as
U
3o6 PREVENTION [Sect.
regards employees of planters, railway companies, etc. Officials
cannot, therefore, have any resource except to persuade and
to keep on persuading, and even then only a proportion of
the people would adopt the measures. For anything like
general protection the Government would probably have to
supply most of the cost — which we have seen will be very
considerable. Of course, in Europe and the United States,
where the people have reached a higher degree of prosperity
than in most tropical countries, this measure is more likely to
be adopted by the general public ; but even in them the very
poor and the agricultural classes are likely to cause great
difficulties. It can, therefore, scarcely be said that general
protection, or even protection of a percentage of houses, is an
easy and cheap measure. Observe, also, that the cost of it
is likely to vary according to the number of houses.
Notes on the cost of mosquito reduction have just been
made. For Mauritius, which contains 705 square miles (1,924
square kilometres) and a population of 534 persons to i square
mile, I estimated that a general mosquito reduction in inhabited
areas, especially in towns, would cost, for minor works alone, the
sum of ;^5,6oo (83,910 rupees) per annum. For making this
estimate I relied upon figures given to me by the Medical
Department, who suggested the number of workmen which
would be required for each village, plantation, town and district,
and the sum includes funds for the director, and travelling
expenses. But it does not include the cost of the major
measures, that is, the drainage of large marshes, and dealing
with such waters as require the advice of an engineer (section
35 (8)). This cost was estimated in Mauritius by the Public
Works Department at a capital expenditure of about ;^42,ooo
(630,000 rupees), but I advised that these major works should
be undertaken only where the minor works might be found,
after experience, to be ineffective.
For the reasons already given it is almost impossible to
furnish any general estimate for mosquito reduction anywhere.
39] COMPARISONS 307
The cost depends upon the number of major works required,
the price of labour, the price of expert supervision, the local
laws, and the local efficiency of administration. It is very
difficult to extricate from the accounts of various campaigns
the money expended on mosquito reduction alone. In the
town of Port Said, however, where there is very little rainfall
and where a complete Culicine reduction has been carried out,
the cost has been about 5d. per head of population per annum
(section 53).
I have already stated that mosquito reduction has the great
advantage that it can be carried out by Government alone with-
out reference to the people. Labourers can be employed to
treat Anopheline waters or to clear away Culicine waters from
the backyards of houses, without causing any real trouble to
the public. It is not necessary for Government officials to go
about persuading householders to do this or that, or for medi-
cal men to examine large numbers of individuals, and so on.
On the other hand, mosquito reduction may just possibly be
essentially unfeasible in places where the breeding waters are
such that they cannot be removed for any cost that can be
afforded by the local funds ; and this is, of course, a question
upon which it is impossible to make general statements.
As a broad rule the cost of mosquito reduction must always
tend to vary according to the area of the country treated. [X
It is often thought, especially by medical men, that the
cost of prevention by treatment is almost nil. We write pre-
scriptions, which cost us nothing and which are made up by the
dispenser ; and we often seem to think that a similar prescrip-
tion can be given, at the same small cost, to a whole nation.
But the cost is sure to be very considerable. For Mauritius
in addition to the mosquito reduction, I prescribed a very
partial scheme of prevention by treatment, costing 30,cxx)
rupees for the quinine alone, 3,600 rupees for its preparation
and despatch, and 6,000 rupees for the services of five quinine
dispensers, amounting to ;£'2,640, or 39,600 rupees, per annum.
3o8 PREVENTION [Sect.
This was without the salary of a director and cost of office, etc.,
and it was proposed that the quinine should be distributed
gratis, but chiefly in intensely infected localities.
Here again the cost must always depend largely upon the
local conditions. A highly civilised and prosperous people will
take the drug readily, where a very ignorant, poor, coloured
population will require the utmost amount of persuasion. Thus
we have to pay not only for the amount of the drug used, and
for its preparation and despatch, but also for an agency which
will distribute it to the people and will persuade them to use
it properly. We are very apt to forget this last and very
costly item. Think for a moment of the position of the very
poor in malarious villages and towns. The occupant of each
house is generally obliged to go to his labour extremely early
in the morning. His wife has her household duties and her
children to attend to. What time have they to obtain the drug
at local dispensaries which may perhaps be miles distant ; and,
very often, what money have they to purchase it near at hand .?
Moreover, neither the man nor the woman has time to force the
medicine down the throats of the younger children. The same
difficulties recur day after day and week after week, perhaps
during the whole of the malaria season, and even beyond it.
Meanwhile patients rebel against the medicine, just as much as
those who care for them rebel against the necessity of fetching
it, and soon there is very apt to be a general rebellion. This
has been strongly felt already in many localities, where pre-
vention by treatment has been much practised ; and in fact it
was for this reason that my advice was sought both at Ismailia
and in Mauritius. Dr Malcolm Watson has also made some
important remarks under this heading (section 57).
In my Mauritius report I laid down that for most tropical
countries the only effective way of giving quinine is {a) to give
it gratis, {b) to give sufficient quantities to last each patient for
one or two weeks or more, and {c) to distribute it actually from
house to house. Now all this must cost the state a very
39] COMPARISONS 309
considerable sum. As a matter of fact a large number of fully-
qualified medical men, and also qualified assistants, must be
employed to carry out this distribution ; and we must remember
that the salary of a fully qualified medical man is as much as
the wages of about fifty coolies (at least in India), and the
salary of a reliable qualified assistant may amount to as much
as the cost of five to ten coolies.
Regarding the feasibility, independent of cost, we must
again remark that this measure does not accord with sanitary
axioms 6 and 7.
The cost will tend to vary according to niiniber of population.
To sum up — protection is evidently a personal or domestic
measure which cannot be forced by any government on the
people, unless the former is willing to supply the nets or screens
to the poor — the cost of which would probably largely exceed
that of mosquito reduction, at least in towns. But protection
should always be adopted for public buildings and isolated
houses, such as railway stations, rest-houses, and houses on
estates. I think that it might also be used, even at the cost
of supplying netting, for villages in proximity to large marshes
which cannot be drained without great expense. At the
same time it should always be urged on the public by means
of lectures, pamphlets and placards, which cost Government
almost nothing, and certainly have a good effect.
Practically, therefore, for public prophylaxis we are called
upon to choose between mosquito reduction and quinine.
Ideally the advantages of mosquito reduction are simply over-
whelming — so much so that I urge it should be universally
adopted in all towns i?i the tropics^ as a part of a general crusade
against vermin of every description. The relief caused by
removal of the mosquito pest is great enough to compensate
for the small cost involved (in towns) even if the insects do
not carry any disease.
Practically, however, our choice is often limited by the
financial position of the place and time. To familiarise him-
3IO PREVENTION [Sect.
self with the question the reader will do well to recall to his
memory various localities which are well known to him.
Suppose, for illustration, that malaria were to break out in
London round Hyde Park in consequence of an obstruction
to the drainage to the Serpentine river. Can we suppose
for a moment that the authorities would not at once under-
take Anopheline reduction by removing this obstruction ?
Would not this be much cheaper and almost infinitely more
convenient than to force people to screen their houses or to
take quinine, while the hypothetical mosquitos are allowed to
remain as numerous as before ? Precisely the same answer
must be given in the case of most cities, towns and even large
villages in the tropics. But now take another extreme case,
and suppose that the disease were to break out in any large
rural area in Europe, such as among the bogs and lakelets
of Connemara. What practical hygienist would urge mosquito
reduction here, with the immense cost involved, merely for
the benefit of a few scattered farm - houses. The appropriate
measures would obviously be protection and quinine, as a
general rule ; but even here, we might occasionally find villages
in which the Anophelines breed in a few local waters which
can be removed at a smaller expense than would be involved
in the other measures. In fact, between the two extreme cases
suggested, there are innumerable instances where either of the
measures or both may be used, and where the director must
use his own judgment.
The cost of reduction of Anophelines tends to vary with
area, and not with population. It does not matter much
whether the area is crowded with houses or not ; though, if
anything, density of population, necessitating well - paved
streets and the removal of agriculture, will tend to cheapen
the cost per unit of area. Thus roughly, the cost of Anopheline
reduction for a square mile of densely-crowded city or town
is likely to be actually less than that of the Anopheline reduc-
tion for a square mile of uninhabited wilderness. In the former
39] COMPARISONS 311
case the expense will benefit a large number of human beings,
and in the latter case only the birds and beasts.
On the other hand, the cost of case reduction and quinine
prophylaxis must vary directly, not with area, but with popula-
tion. It will be vastly greater in a crowded square mile than
in a square mile containing only a few cottages. Therefore
evidently mosquito reduction is called for by every considera-
tion in the case of crowded areas, and, on the other hand,
quinine tends to be the more proper ipeasure amongst a
scattered population, where Anopheline reduction would be
too expensive for the local funds. This is, of course, a general
rule, exceptions to which must be carefully considered by the