there was no one who objected to the visits of the mosquito
brigades, nor were there any complaints that any member of
them had abused the privileges conferred on European subjects
by the Capitulations. In fact, the Capitulations put little real
difficulty in the way of sanitary reform. Europeans and their
consuls are fully alive to the possibilities of scientific measures
properly carried out ; and if Europeans and even natives are
assured that efforts to improve sanitation are made con-
scientiously, I believe that they will forego, as has been proved
by the mosquito campaigns, the one privilege which they
prize, namely, an immunity against interference by Government
officials. The difficulty caused by the domicile clause of the
Capitulations, which is used as a cloak for nearly all adminis-
trative sins, vanishes in the face of a mosquito campaign. The
experience gained in Cairo and Heluan proves conclusively that
mosquito destruction is a desirable measure to be adopted in
Egypt, and it is remarkable that this fact was not appreciated
before.
Unfortunately, Sir Horace Pinching, who had been so
sympathetic towards this work, retired in the autumn of 1907
from his post of Director-General of the Department. His
successor immediately told me that he did not consider it
necessary for me to continue the work, and he treated me in
such a manner that I was obliged to resign my appointment in
the Department. At the same time my brother, E, H. Ross,
was also threatened in my presence with dismissal. It will
therefore be understood that since these events the Government
has become lethargic about anti-mosquito measures. 1 have
heard that mosquitos have returned in the parts campaigned
528 MOSQUITO REDUCTION IN EGYPT [Sect.
in Cairo ; and at Heluan, and even Port Said, the pest is
reappearing. I have seen frequent complaints in the Egyptain
newspapers that the campaigns have been allowed to fail, and
I fear that for the time being mosquito destruction has fallen
into disrepute in Egypt.
From my experience of the Public Health Department,
I think that the Government does not appear to appreciate
its responsibility regarding sanitary administration. A visit
to Cairo will show that nearly all improvements are made
by private enterprise. When a new town is started, such as
Heliopolis Oasis, it is started by a company. The most modern
buildings in the city itself, erected for the public, have been
built by His Highness, the Khedive, on his own private property.
Yet the Government owns nearly all the vacant land round the
city, and it refuses to part with it. The result is that the
city is becoming overcrowded, with an enormous death-rate.
Calculated on the 1907 census, the death-rate of Cairo was,
for 1908, 39"23 per 1,000, and for 1909, 44*9 per 1,000. In an
article published in the British Medical Journal on loth April
1 910, which describes the state of the sanitation of Cairo, it is
stated that 28*2% of the infants born in Cairo die during the
first year of life ; and 48'5%, or nearly half, of the children born
will, if the present death-rate continues, die before they reach the
age of sixteen years. When I was in Cairo, in certain districts
in the Saida Zenab quarter, known as El Mardi and El Sakkia,
Government properties, the death-rate reached 20^, and yet the
Government will not allow the city to expand, and appears to
await a rise in the value of the property before it will part with
it. My personal opinion is that the fault is due to the fact that
the country is governed almost by amateurs. The sanitary
officers are not bound to obtain Public Health Diplomas, and
it seems to me that many of the higher Government offices are
placed in the hands of friends and relatives of existing officials,
apparently without regard as to qualification. I have shown
that the laws are difficult to enforce. There is no building
53] REMARKS 529
law whatever ; anybody can build any hovel he pleases. Few
reports are published from the Public Health Department, and
officials under the present regime are not permitted to print the
results of their work for the benefit of their successors.
Mosquito extermination, however, is bound to be undertaken
seriously in Egypt under more competent management. For
the time being, perhaps, it will remain in abeyance, but it is a
measure which is so certain in its results and so far-reaching in
the good which it does, that before long, I think, it will be
generally demanded by the public. It is nauseating to live in
Cairo in the summer and to be bitten persistently by insects
which breed in excrement. Mosquito destruction is an un-
pleasant though a simple problem. It must be continued
unremittingly, or the gnats will return ; but the cost of the
campaign will fall to a certain extent after the initial destruction
of the pest. I hope that the work will be started throughout
Cairo, for I know that the results will be greater than were ever
anticipated.
By ANDREW BALFOUR, M.D, B.Sc, F.R.C.P. Edin.,
D.P.H. Camb.
Director, Wellcome Research Laboratories, Gordon College, and
Medical Officer of Health, Khartoum
54. The Campaign at Khartoum. — In the pre - Dervish
days Khartoum must have been a hot-bed of mosquito Hfe.
This is apparent from the evidence of Sir Rudolph Baron von
Slatin, who states that mosquitos were very prevalent during
this period, and from that of Father Ohrwalder of the Austrian
Mission, who asserts that he was sometimes driven to go and
stand up to his neck in the Nile in order to avoid the attentions
of the winged hordes. That malaria was also present cannot
be doubted. Schweinfurth speaks of the unhealthiness of the
place in a manner which leaves little doubt but that one of
the chief causes of the high mortality which obtained at certain
periods was malarial fever. It is believed that its evil reputa-
tion was one of the reasons which induced the Mahdi to
abandon its site altogether, and, with that empirical wisdom
which often characterises the native, to found Omdurman on
a spot where the river banks are not bold and terraced but
shelving, and consequently free from pools at low Nile. Some
four years after the new city had come into being, a survey of
the conditions as regards mosquito prevalence was made. This
disclosed the fact that three genera, represented by three species,
were constantly present, namely, in order of frequency, Culex
fatigans, Stegoniyia calopus and Pyretophorus costalis. Malaria
was found to exist, and it was shown that infection could be
acquired locally, while numerous cases were always being
brought into the town by steamers coming from the highly
malarious regions to the south. It was towards the close of
530
Sfxt. 54] BREEDING-PLACES 531
1903 that anti-mosquito measures were instituted and a small
mosquito brigade established. These measures have continued
in force ever since, and the brigade has been constantly
employed ; for one of the chief points elucidated by the work
is the absolute necessity for its continuity. In a place like
Khartoum it is essential to carry out preventive measures
year in and year out, and two mottoes most suitable for those
in charge might well be " Weary not in well-doing," and " Do
not put overmuch trust in the native inspector."
In this brief note we are only concerned with the single
species of Anopheline which constitutes itself a danger to the
town, and may omit any detailed account of the work in
connection with the two other species of Culicid mentioned ;
but it is well to point out that in practice these latter cannot
be neglected. Mosquito prevention measures must be general,
and it is very often the operations against Culex or Stegomyia
which lead to the discovery of invasion or threatened invasion
by Pyretophorus.
P. costalis, then, is the malaria carrier of the Northern
Sudan, and so far as Khartoum is concerned its breeding-places
were found to consist of: —
(i) Pools left by the falling Blue Nile. These are found
for the most part in the sand-banks which appear in
the river's bed, but may also occur in the sloping
and terraced banks as the river falls.
(2) Garden tanks.
(3) Bath-waste pits.
(4) Permanent garden pools,
(5) Sakia pits, as used in irrigation work.
(6) Irrigation channels and pools formed by leaking
" gudwals," as the large and small canals are termed.
The only large area of irrigated land is at Khartoum
North.
(7) Wells.
(8) Rain-water collections.
532 THE CAMPAIGN AT KHARTOUM [Sect.
(9) Household water collections, such as water stored in
barrels. These are not at all common.
(10) Water collections on steamers, provided these be
exposed to the light, i.e., in boiler trays, cisterns, etc.
(11) Chance water collections, as in old barges and leaky
boats where speedy water evaporation is prevented.
One or two of these breeding-places merit a few words of
explanation. The soil in some parts is what is termed "weep-
ing." It contains a large quantity of salt. Hence if gudwals
are constructed of this soil the water dissolves out the salts,
and leakages soon result, pools form, and, despite the fact
that the water is brackish, P. costalis readily lays her eggs in
such collections. This mosquito is very rarely found in wells,
but its larvae have once been encountered in a well 70 feet
in depth. This is so peculiar that one wonders if they had
not been accidentally introduced. Rain-water collections are
rare in Khartoum, but occasionally the summer is compara-
tively wet, and then pools and puddles may persist for some
time. They are not commonly utilised as breeding - places
by P. costalis. This Anopheline is not often found breeding
out on the river steamers, but has been known to do so, and
may be introduced into Khartoum as imagines both by steamers
and by native boats. Recently a species of Nyssorhynchus
has been apparently introduced in this manner. It is worth
noting that since operations were started cases of malaria
locally acquired in Khartoum have never once occurred with-
out the presence of Anophelines in or near the town being
demonstrated.
The chief methods of prevention and reduction put in
force may be tabulated as follows : —
(i) Systematic inspection.
(2) Notification of cases of malaria.
(3) The issue of warning notices and distribution of
information.
(4) Petrolage.
54] DETAILS OF MOSQUITO REDUCTION 533
(5) Filling in of pools and abolition of water collections
such as garden tanks, bath-waste pits, etc. Also
the screening of cisterns.
(6) The introduction of fish into water channels.
(7) The piping and covering of raised water channels to
prevent leakage through their banks.
(8) The imposition of fines.
(9) General legislation as regards borrow pits, irrigation,
engineering work, and the provision and maintenance
of dry zones.
All three forms of malaria used to occur in Khartoum.
Benign tertian was the most common, malignant next, while
quartan was rather infrequently encountered, though it has
been found to be much commoner than was at first supposed.
Quite a large number of cases harbouring crescents annually
come into the town from the Upper Nile and the Bahr-el-
Ghazal Province.
Some of these measures call for a little further notice. The
inspection must be thorough and the native inspector must
be controlled by trained and reliable British sanitary inspectors.
The town is divided into sections, each of which is in charge
of a native who has no sooner completed his round than he
begins again. In this way, if he does his work properly the
inspector should visit every house and every water collection
in his district at least once a week. The British inspectors
are responsible for the whole town, and often combine mosquito
work with house-to-house inspection. Areas bordering on the
river, the point of danger, are in charge of the most experi-
enced men, and a special native inspector is detailed for
steamer and boat work. Khartoum has a population of some
16,000; Khartoum North, of about 25,000; and there are in
all at the present time three British sanitary inspectors^ and
seven native inspectors. Of these one British and two native
inspectors are responsible for Khartoum North, where with
^ Mosquito prevention is, of course, only a part, though an important one, of the
work of these inspectors.
534
THE CAMPAIGN AT KHARTOUM
[Sect.
the exception of some pools on a sandy island there are no
river pools, the banks being high and steep, and, where there
are scarcely any gardens, the only dangerous area, so far as
P. costalis is concerned, being a large stretch of irrigated land
and certain small irrigation channels which are apt to leak
and form pools. The dockyard is situated at Khartoum North,
and the steamers require constant attention, but more for Culex
and Stegomyia than for Pyretophorus. When necessary, extra
men are employed filling in river pools ; and if these happen,
as at present, to exist in sand-banks opposite the so-called
British Barracks, the services of the British troops tenanting
these latter are at once solicited, and never in vain.
Notification has proved of great value. It stimulates
enquiry and has often led to the discovery of breeding-places
when such would otherwise have been missed.
Here are types of the warning notices inserted at intervals
in the local press, especially during the winter when the Nile
is falling, and again during the brief rainy season in August
and September.
SANITARY NOTICES
"The attention of householders
and others is again called to the
necessity of properly emptying and
drying out zeers and other vessels
holding water at least once a week,
in order to prevent mosquitos find-
ing breeding-places. Persons pro-
ceeding on leave are especially
requested to see that this is done
before premises are left vacant.
Any one found harbouring mosquito
larvae or pupae on his premises is
liable to be punished in accordance
with Town Regulations ; and in
future stringent action will be taken
to put an end to this nuisance
and danger to health. It is not
enough to instruct servants to carry
out these measures. There must
be personal supervision. Five
minutes per week is no great tax
on the time of any one."
" Householders are urgently re-
quested to give immediate notice
to the Sanitary Inspector at the
Mudiria if they find themselves
troubled by mosquitos or note their
presence. Any one found harbour-
ing larvae or pupae on his premises
is liable to be fined ; and stringent
action will be taken, as malaria-
carrying species are at present
endeavouring to obtain a footing
in the town."
54] ANTI-LARVAL MEASURES ON STEAMERS 535
The regulations as regards steamers are of practical interest
and are also given below. When carefully followed the results
have been excellent.
" I. Before leaving Khartoum the bilge water in the various
sections should be oiled by pouring petroleum on the surface
of the water and stirring well with a stick. A film will then
form on the surface, which prevents access of air to the mosquito
larvae and pupae, and so kills them. Eggs deposited by mosquitos
on this oil film will not develop, and many of the females
themselves will be killed. Roughly, about one half-pint of
oil should be devoted to each section. A little experience
soon shows how much or how little oil is needed to form a
proper film. In addition, the water in the trays under the
boilers should be examined, and, if necessary, oiled.
" A cup or wide-mouthed bottle can be used for collecting
water for examination. The vessel should be quickly but
gently dipped under the surface and lifted out without spilling
any of the contents. For somewhat inaccessible places a tin
with its bottom replaced by wire-gauze mesh and attached to
a stick is useful. The larvae are then found wriggling on
the gauze. Such a collecting dish is easily made and answers
well. It should be examined in a good light. It is to be
remembered that any standing water collections will harbour
mosquito larvae, and attention should therefore be paid to
the water-closet cisterns, zeers and tanks.
" 2. During the voyage, opportunity should be taken to re-
oil the bilges wherever possible. This should especially be
the case before starting on the return journey. Wood holds
are usually at fault. The difficulty can be got over by empty-
ing these in rotation, so that the water in the hold can be
got at and oiled once in every fortnight. Special attention
should be directed to zeers when these are used for storing
bottles of drink. All zeers should be emptied out at least
once a week during the voyage.
" 3. The thing to be avoided is returning to Khartoum with
mosquitos on board. If this is done, wells and water collections
in the town which have been cleared at trouble and expense
are liable to become reinfected. This has happened repeatedly,
so that it is very important that steamers should arrive clean
and free. It is well to have all bilge water emptied on arrival,
and all steamers lying up should be inspected and treated
in the manner described. Similar precautions are required
as regards barges, sandals, launches and any vessel on which
there is stagnant water.
536 THE CAMPAIGN AT KHARTOUM [Sect.
"Note. — It has been proved that mosquitos, as a rule, will
not stay for any length of time on a steamer if they are
prevented from breeding out on board. Consequently, such
preventive methods are effective, as has been demonstrated
on several occasions ; and there is no excuse, in most instances,
for steamers reaching Khartoum with their bilge water, etc.,
full of larvae and pupae, and their cabins full of adult mosquitos.
" Sometimes it has been found advisable to employ sulphur
squibs when there were many adult insects in the holds."
A little space may be devoted to the introduction of fish
which has been successfully employed in the irrigation channels
at Khartoum North and, as will be seen, elsewhere in the
Sudan.
A zealous and interested official some time ago suggested
the introduction of the small " millions '" fish {Girardinus poecil-
loides) from Barbados to cope with larvae in swamps, irrigation
channels, large pools and like collections of water. The question
was referred to me, and I found myself opposed to the idea,
partly because I know the difficulty of transporting these fish,
and the possibility that they might not take kindly to new
surroundings, and partly because, like the proud Syrian of
old, I was tempted to reply : " Are not Abana and Pharpar,
rivers of Damascus, better than all the waters of Israel ? " In
other words, one was of opinion that there was no use going
outside for what might very well be obtained at home. I knew
that Captain Flower, Director of the Zoological Gardens at
Ghizeh, employed young " Bulti " {Tilapia niloticd) in the tanks
of the aquarium at Ghezireh, and found them most efficient in
keeping the water free from mosquito larvae, and it was reason-
able to suppose that many Nile fish were effective, especially as
it is found that when fish are present in any pool left by the
falling river, mosquitos do not breed out therein.
There were two points, however, requiring attention. If any
water collection is stocked with fish, these latter are apt to be
speedily cleared out by natives or birds, such as king-fishers,
which are very plentiful. Moreover, as is explained later, fish
54] LARVIVOROUS FISH 537
which attain any size are not suitable for use on irrigated land.
Hence, it was desirable to find a small and greedy fish which
would offer no temptation to the native, which could be used
in irrigation channels, and which, though not immune from
the depredations of fish-loving birds, yet was so prolific, or
could be used in such numbers, as to make these ravages of
little account. The type of fish desired was that known in
India as the Chilwa {Chula argentea), which is said to be more
efficient than " millions," as not only does it devour the larvae
but, being a surface-feeder and an eager fly-taker, it is deadly
to the adult mosquito, especially to the female intent on egg-
laying.
As Mr Harold King, our entomologist, was going up the
White Nile in the Floating Laboratory on a voyage of discovery,
I asked him to take every opportunity of studying the question.
Mr King is an excellent field-naturalist, and admirably fitted
to carry out such an investigation. His report, which I append,
will be found of interest and value, and it would appear that
in Cyprinodon dispar we have obtained the fish we require.
This, as Mr King remarks, remains to be proved, but the
following letter, kindly sent me by the Acting Manager, Sudan
Plantations Syndicate, in whose irrigation channels the fish
are being tested, is at least promising : —
"Dear Sir, — In reply to your favour of the 19th inst.
I have examined the small canal into which the fish have been
introduced.
" The canal is about thirty metres long and about half a metre
deep, and the opening to the larger canal is closed with gauze-
wire netting to keep other fish out. Although the still water
is now lying twenty-five days there are no signs of mosquito
larvae.
" The fish are alive and seem to feed on flies on the surface
of the water, and are most active in the early morning. — Yours
faithfully, Alex. MacIntyre."
Like Mr King, I ha\'e fed Ophiocephalus obscurus {vide infra)
on the larvae of Pyretophorus costalis, and noted how the
538 THE CAMPAIGN AT KHARTOUM [SecT.
latter were devoured before ever they reached the bottom of
the jar.
The following is Mr King's report : —
"While on the White Nile, between the dates of 17th April
and 19th July, I carried out some investigations with Nile fish
with a view to ascertaining what species, if any, were likely
to be of value in controlling mosquitos by feeding on their
larvae. In most of the swamps, where mosquito larvae
abounded, shoals of small fish of various species also occurred,
but from the fact that the two throve together it was evident
that the fish were not likely to be of very much use. Numbers
of these fish were captured, placed in jars and offered mosquito
larvae, but with one exception they refused them until they
had passed one or more days without food. The exception
was a fish found in a khor between Gebel Ahmed Aga and
the river. In this khor very few mosquito larvae could be
found — a search of nearly two hours resulted in less than a
dozen specimens being taken — but there were present numbers
of the young fry which has been identified by Mr G. Boulenger
of the British Museum as Ophiocephalus obsairus.
" This fish feeds greedily on mosquito larvae, thrives well in
captivity and in stagnant water, and appears to be an ideal
fish for the purpose for which it is wanted, except in one
respect, viz., size. When full grown it attains a length of
35 centimetres. As fry, inhabiting shallow waters such as are
found in swamps and river-spills, this fish would no doubt prove
of value, for it is in just such places that mosquitos breed. On
the other hand, though the fish would flourish in large irriga-
tion canals, and the fry could reach the smaller gudwals on
irrigated land, the latter are frequently so constructed that the
young fish on increasing in size could not regain the parent
canals and would perish. Hence this species of fish is not
likely to be an economical means of dealing with mosquito
larvae in such situations.
" Some thirty specimens of 0. obscurus are still living in a jar
in the Laboratories.
" During May, I met Mr Butler, superintendent of game
preservation, who told me of a small fish — Cyprinodon dispar —
which lives in Khor Arbat, about twenty-two miles from Port
Sudan. He very kindly furnished me with some notes on its
habits, and recommended that it should be given a trial as it
appeared to him to be likely to give good results. He further
said that, while no mosquitos are noticeable in the vicinity of
54] LARVIVOROUS FISH 539
that khor, they are plentiful near other similar khors where
C. dispar does not exist.
" Accordingly, on 6th September, I left for Khor Arbat and,
having spent three days there, returned to Khartoum on 12th
September. There were myriads of the fish in the khor, but
at first I had considerable difficulty in persuading them to live
in captivity. Eventually, I found that while, if placed in jars
nearly full of water, most of them died within twelve hours,
yet if given only about two inches of water over a layer of sand
they could be transported fairly easily. One hundred and one