NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
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lights, on entering a house are frequently crushed by the occupants lying on
them, and the resulting blisters soon become chronic sores with indurated mar-
gins and closely simulate the true Cambay Boil.
As far as I am aware, no observer has as yet carried out exact feeding
experiments with bred house flies in the endemic area, with a view to proving
or disproving the fly transmission hypothesis. In my studies on the herpeto-
monads of the house flies of Madras I had already mastered the best methods for
breeding these insects and keeping them in captivity. During June, July and
August in Cambay, Musca nebulo Fabr. and Musca sp . were extremely abun-
dant, and I do not recollect having seen these insects in such large numbers
and constituting such a pest, in any part of India which I have visited. While
driving from the dâk bungalow to the Hospital where I conducted my experi-
ments, they followed me in large numbers, and in the Hospital itself they were
present in swarms; so much so, that it was difficult to carry on one's work.
EXPERIMENT I.
CAN THE HOUSE FLY CARRY THE PARASITES ON ITS LEGS (PULVILLI) OR ITS
PROBOSCIS, FROM A SORE DISCHARGING PARASITES, AND DEPOSIT
THEM ON A SCRATCH OR ABRASION ON THE SKIN OF
A SUSCEPTIBLE PERSON ?
This experiment was carried out on my own person; several scratches and
abrasions were made on the dorsum of my left hand, and flies were caught
which had already crawled over and sucked up the whitish discharge from the
sore mentioned above, and which was teeming with apparently living parasites.
They were then allowed to crawl over and suck up the serum from the scratch-
es on my hand. This experiment was carried out daily for about a month, and
it was impossible to prevent the experiment under consideration being also
carried out naturally, not only on my left hand, but on the right, and more
particularly on my face ; small cuts such as are commonly caused in shaving
were constantly being contaminated by flies which had previously been on the
sore. In spite of all these attempts, however, I never developed a single lesion
on any of the experimental spots, and now more than a year has elapsed since
they were carried out. Such a series of experiments, conducted in the endemic
area, and under the most favourable conditions, conclusively prove that the
house fly does not carry the parasite in the way mentioned above. In support
of these results, there are the statements of the people of Cambay, who, al-
though they have very crude ideas of the disease and its origin, have no hesi-
tation in saying that the sore never begins in an open cut, scratch or abrasion,
but always in a sound portion of skin.
5
In favour of the fly transmission hypothesis there is the undoubted fact
that people, particularly children, who have a sore discharging parasites, fre-
quently reinfect themselves by scratching the scab or the surroundings of the
sore, and then scratching some other healthy part of the skin. The case I was
studying thus reinfected himself, and it is interesting to note that at the time
he had a great deal of prickly heat, and inoculated three places by scratching
them with infected nails. When the rationale of this auto-infection is carefully
considered, it will be seen that it is exactly similar to vaccination with cow-pox,
for the parasite is deliberately inserted into the skin in the act of scratching.
This method of auto-infection is extremely common, and the Jews in Baghdad
and other parts of the world, have long practised it ; recognising the readiness
with which a sore can be produced on any part of the body they select a
place where the resulting scar will cause no disfigurement.
Several experiments were carried out to try and see whether an already
existing sore, (not the specific lesion) will become infected by placing some of
the whitish discharge containing parasites on the surface of the granulations,
such as a fly may do in the act of crawling over it. The experiments were car
-ried out on three susceptible people who had recently come to Cambay, and in
each case they failed. Lastly, a large number of sores, ulcers, scratches and
abrasions in children, who had up till then not contracted the disease, were
examined for months, but I was never able to find a single parasite in any of
these sores. I consider this observation to be of importance, for it refutes the
numerous loose statements, that during the fly season, when the sores are most
prevalent, such cuts, abrasions, and ulcers are very liable to become infected
with the parasite. These experiments, then, not only prove that the house fly
is not a carrier in the way suggested, but that simple sores and ulcers which are
so common, and always present on Indians, never become infected.
EXPERIMENT II.
DOES THE PARASITE WHEN INGESTED BY THE HOUSE FLY UNDERGO ANY DE-
VELOPMENT, OR DOES IT REMAIN LONG ENOUGH UNCHANGED IN ITS
ALIMENTARY TRACT, SO THAT LATER IT MAY BE PASSED OUT IN
ITS EXCRETA ON TO THE SKIN OF A SUSCEPTIBLE PERSON ?
In order to carry out this experiment, flies ( Musca nebuloa n d
M u s c a s p
. )
were bred out from larvæ and kept in suitable cages ; they were then taken out in
small numbers in large glass tubes, and allowed to feed on the sore, just at the
time when it was discharging parasites. They were next placed in a clean jar
and examined at regular intervals ; many of the flies were repeatedly fed.
c2
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Their alimentary tracts were dissected out in sterile salt solution and each se-
parate portion was isolated and smeared out, and then stained by Romanowsky's
stain. It was found that the parasites could be recovered only in the midgut,
and unchanged, up to six hours after they were ingested, but that after that
time they degenerated and disappeared. Most careful search was made in the
hind part of the fly's intestine, particularly the rectum, but I was never able
to recover a single parasite. These experim ents clearly prove that though the
fly undoubtedly often ingests parasites, they never undergo any development
in its alimentary tract, but on the contrary, they soon degenerate as shewn in
the smears when stained by Romanowsky's stain. A large number of
wild flies were next examined, more particularly those which had already
fed on the sore, but here again the parasites were never seen after six
hours ; the wild flies in Cambay were almost all heavily infected with herpe-
tomonads and bacteria. The second experiment therefore proves, that in Cam-
bay the alimentary tract of the house fly is not a suitable medium for the para-
site, and that it never develops into a flagellate, but soon disintegrates and
disappears. The results of these experiments are directly opposed to those of
Row and to some recent observations made by Cardamatis and Melissidis who
believe that the house fly is the invertebrate host of the parasite of Oriental
Sore. Row, in his most recent communication regarding the method of trans-
mission of the parasite, still a theres to the house fly (species not named) as the
probable transmitter ; he now however admits that the parasite soon disappears
from the alimentary tract of a fly, an observation which I made more than a
year ago in Cambay. This, in my opinion, definitely proves that the fly cannot
infect another person by its excreta. He now pins his faith to the transmission
of the parasite up to three hours after it has been ingested, and suggests that a
fly so infected is capable of passing out living parasites, and that these may be
deposited on a cut or abrasion or scratched in to the skin. He believes his view
is proved by the fact that he has succeeded in infecting a monkey with the con-
tents of the midgut of a fly which had ingested infected material three hours
previously. I may, however, point out that this is no proof that the fly acts
as the natural carrier : Basile has carried out a very similar experiment with the
dog flea and the parasite of dog Kala Azar. Such an experiment merely indi-
cates that the parasites remain alive, after having been three hours in the
stomach of the fly, (which in this case was a clean insect) and is analogous to
keeping the infected material in a test tube. In order that the transmission
may take place, in. the manner now suggested by Row, it is necessary for the
flies to have clean alimentary tracts, whereas the wild flies in Cambay, judging
from the contents of their stomachs, live almost entirely on filth. One of the
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most convincing arguments against the fly transmission hypothesis, is the fact
that although flies were most abundant during the rainy season in Cambay, I
never saw a single early case which I could say was definitely infected during
this time. From October to January I regularly examined some eight hundred
children in three of the local schools, and although a number of them had not
yet contracted the disease, I failed to find a single early lesion. The skin of
each child was thoroughly searched, and any suspicious pimple or nodule was
punctured and the contents microscopically examined. Further, if the trans
-mission is regularly carried out by the fly, as suggested by Row, surely I would
myself have become infected, for all the factors mentioned by him were cer
-tainly present in my case, with the exception that the flies did not ingest the
parasites along with blood, which he states is essential for them to live and
develop in. I find it difficult to understand how a non-bloodsucking fly, such
as Musca nebulo , can obtain blood from a sore, for the only medium in which
I found the parasites discharging from the sore, was a whitish fluid containing
leucocytes. Lastly, the fact that the disease never spreads in a house during
the fly season, even when several people with sores in a suitable condition are
present, is I think very strong evidence against the fly transmision hypothesis.
In Cambay the disease is most frequently contracted during the cold weather,
which is very severe, the thermometer frequently registering a few degrees
above 0°C, and at this time of the year house flies are very scarce.
Cardamatis and Melissidis state that the parasite of Oriental Sore in
Greece (?) lives as long as six days in the alimentary tract of the house fly
(species not stated), but they do not say whether they used bred flies in their
experiments. From the fact that wild house flies are commonly infected with
several species of herpetomonads, such experiments as they record are of little
or no value.
EXPERIMENT III.
IS THE PARASITE TRANSMITTED BY LICE,—PEDICULUS VESTIMENTI
AND PEDICULUS CAPITIS L. ?
It may be thought that lice are the most suitable carriers of the parasite,
more particularly the species found on the body, as they may crawl over a sore,
and thus become infected. Later they may be transferred to a susceptible person
and infect him. A large number of body and head lice were obtained, the
former with great difficulty, they were then kept on small pieces of cloth, in
glass tubes, and regularly fed on the case mentioned above ; others were allowed
to crawl over the surface of the sore, and to suck up blood from the margin.
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Many lice were bred, and then fed from the first instar up to the mature
insect. Their alimentary tracts, salivary glands, and other organs, were regular
-ly examined in fresh and in stained preparations, but not a single parasite,
either changed or unchanged, was found in any of them. I could therefore
come to no other conclusion but that lice ( P. vestimenti and P. capitis) are not
the natural invertebrate hosts of the parasite. The statements of the people
themselves confirm these results ; educated Indians of high caste, who wash
daily and change their clothes often, and who practically never harbour body lice,
and very seldom head lice, contract the sore as readily as people who never
wash and who harbour such vermin. Further, Europeans who have contract
-ed sores in Cambay, particularly the case of a lady who had one on her lower
lip, strongly oppose the idea that lice are the transmitters.
EXPERIMENT IV.
IS THE PARASITE TRANSMITTED BY ANY SPECIES OF MOSQUITO
OR OTHER BITING FLY ?
In Cambay Stegomyia sp . was extremely common throughout the year
;it is a voracious blood sucker, often biting through clothes. A large number of
these mosquitoes were bred out in the laboratory, and fed in test tubes on the
case, some on the margin of the sore, and others on distant parts. They were
examined at regular intervals, but I was unable to find any parasites, either
changed or unchanged, in any of these mosquitoes ; they were not infected
with a natural herpetomonas, which in the case of mosquitoes comes through
the larvæ. There was then no evidence whatever to shew that this species of
Stegomyia was the natural carrier.
No other species of mosquito was experimented with chiefly for the reason,
that, as I was working single handed, I was unable to collect larvæ in suf
f i - c i e n t n u m b e r s t o c a r r y o u t e x p e r i m e n t s , a n d a l s o f o r t h e r e a s o n t h a t i n C a m b a y
the localised nature of Oriental Sore strongly opposes the hypothesis that a
flying insect is the carrier. As I have pointed out ahove, the railway staff,
who live around the station, about a quarter of a mile from the endemic area,
never contract the disease. This is a very striking fact, for flying insects such
as house flies and mosquitoes, which may have become infected in the town
itself, would have every opportunity of biting people living just on the
outskirts.
Phlebotomus sp., probably baba Annandale, was only seen during the rainy
season, June to September, and then in small numbers. I was bitten by a few
of these flies hut with negative results ; four specimens caught in the Hospital
9
were examined, but nothing was found in them. During the cold weather, this
fly was never seen or felt, although it was carefully searched for in likely
places ; owing to its painful bite it is well known to the inhabitants, but I could
obtain no information which would spew that there were any present during
the cold weather when the disease is most frequently contracted.
Philaematomyia insignis Austen, a common cattle fly, was abundant in
Cambay throughout the year, but I was unable to obtain any positive inform
-ation that this fly bites human beings ; I have only known it to bite man on
three occasions in Madras. It never contains any flagellates.
Stomoxys calcitrans, also common in Cambay, rarely, if ever, bites human
beings ; it is frequently infected with a natural herpetomonas. No feeding
experiments were carried out with either of these flies.
Two non-biting flies, Musca pattoni, Austen, and Musca convexifrons,
Thomson, are common in Cambay, and, as in Madras, they have the remark
-able habit of sucking up the blood which exudes from the bites of Philaemato
-myia, Stomoxys, Tabanus, Chrysops and Haematopota inflicted on cattle
.They were never however seen sucking up the discharge from sores.
In view of the recent work of Basile, that the dog flea Ctenocephalus
canis * is the probable transmitter of Canine and Infantile Kala Azar, and see
-ing that street dogs were numerous in Cambay I endeavoured to find out
whether fleas could have anything to do with the transmission of the parasite.
These dogs seldom, if ever, go into the people's houses, but live entirely on the
streets, and I never saw or heard of a single one having a true Oriental Sore.
Fleas ( Pulex irritans and Ctenocephalus felis were chiefly prevalent during the
cold weather, but I was unable to get them in sufficient numbers to carry out
feeding experiments and the inhabitants of Cambay could give me no infor
-mation regarding these fleas as being the probable carriers of the parasite.
With regard to fleas, it should be remembered that they are commonly infected
with natural flagellates, crithidia and herpetomonads, for Miss Porter has
recently recorded a crithidia from the alimentary tract of Pulex irritans and I
have found a species of herpetomonas in Ctenocephalus felis, indistinguishable,
both in its preflagellate and flagellate stages, from the parasites of Kala Azar
and Oriental Sore. This herpetomonas is found in about 5 per cent. of this flea,
and probably also occurs in C. canis . It is important to note that the flea ac
-quires the infection in its larval stage and that unless this fact is remembered, it
would be very easy, on finding flagellates in an adult flea taken off a dog infect
-ed with Kala Azar, to come to the conclusion that they represented stages in
the development of the dog parasite. The figures and descriptions given by
* I have it on the authority of the Hon. N. C. Rotschild that there is no such flea as Ctenocephalus
serraticeps, and that the flea mentioned by Basile is none other than Ctenocephalus canis.
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Basile exactly coincide with what I have found in Ctenocephalus felis; I have
examined over 400 cats in Madras and have never found them infected with
any such parasite.
EXPERIMENT V.
Is THE BED BUG CIMEX ROTUNDATUS THE TRUE INVERTEBRATE HOST OF THE
PARASITE OF ORIENTAL SORE ?
In order to settle this question beyond dispute, I bred a number of bugs
through three generations in Madras and took them with me to Cambay.
They were fed regularly during June, July and August on the case mentioned
above, some in the vicinity of the sore and others at distant parts. In order
that there may be no misunderstanding with regard to my feeding experiments,
I wish it to be clearly understood that a bug cannot possibly dislodge the para
- s i t e s w h e n i t i n s e r t s i t s p r o b o s c i s i n t o t h e m a r g i n o f a s o r e . I t s p r o b o s c i s i s
not long enough as the parasites are deeply situated, so that the blood it
sucks up, can only come from that which is circulating at the spot. Bugs
will not feed on the surface of a sore which is discharging parasites. This was
definitely settled by feeding bugs at the margin of a sore, and then examining
their stomach contents immediately afterwards. The large macrophages or
free parasites were never found. Although, in a few of the bugs, unchanged
parasites were found, no development was seen in about 250 examined. My
attention was next directed to the probable explanation of the failure of the
-parasites to flagellate in the bug. Early in my investigation I heard of a case
of Oriental Sore in a Parsee boy who came to Cambay for the first time in the
beginning of December 1909, and who left Cambay about January 5th, 1910.
On returning to Bombay he contracted a mild attack of small-pox, and about
three months after leaving Cambay, a small red spot was noticed on his cheek.
This slowly developed and eventually proved to be a true Oriental Sore; later
two other sores formed on his body. There could be no doubt regarding the
time of the year when this boy contracted the disease. This at once led me to
make a careful enquiry into the histories of those people who had had occasion
to come to Cambay for short periods, and it was definitely found that about
95 per cent. of the sores were contracted during the cold season which extends
from the middle of October till the end of February. Having ascertained these
facts, I at once decided to continue my feeding experiments with bugs and to
simulate as near as possible the cold weather conditions; the bugs after being
fed, were kept in a small tin box surrounded with ice. These experiments
were begun on July 25th, 1910, and on August 8th, on dissecting one of the
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bugs, a nymph approaching its last ecdysis, about twenty pairs of actively
dividing flagellates were recovered. There could be no doubt as to the origin
of these flagellates, for in the first place they were found in a bug which had
been bred in Madras and brought to Cambay, and secondly, although I have
examined between 2,000 and 3,000 bugs from different parts of India, I have
never yet found them to contain flagellates, other than those obtained as a
result of feeding experiments.
Having proved that the parasite of Oriental Sore can, and does, reach the
stomach of the bug C. rotundatus when it is fed on the peripheral blood, and
that when such bugs are kept at a suitable temperature (from 22° to 25°C.) the
parasite will develop into a flagellate ; I decided to feed a large number of
bugs on the case, and then to take them down to Bombay and to feed them on
suitable people there. Through the kindness of Surgeon-General Bannerman,
the then Director of the Bacteriological Laboratory of Parel, Bombay, I was
able to feed these bugs on the Laboratory peons. Though they were fed for
about a month, and since then a year has elapsed, none of these men developed
any sores. I returned to Cambay and fed another series of bugs on the same
case and on taking them to Bombay they were fed on other suitable people.
These experiments, however, also failed. There were no young nymphs among
the bugs used in these experiments, almost all being adults. On returning to
Cambay for the second time, I found that the sore was now useless for further
experiments as the parasites had disappeared. I was therefore compelled to
search for another case, and a suitable one was not found till December 1910.
In the mean time I examined a large number of cases but unfortunately none of
them were suitable for experimental purposes. The new case had no less than
five sores, four situated on the right arm, and one on the dorsum of the left
foot : he had already had two the year previously. On puncturing the sores
particularly those on the arm, they were found to be extremely rich in para-
sites, numbers of the polymorphonuclear leucocytes being infected. A large
number of bugs were obtained from Bombay and were fed on the boy's right
arm, at a distance from the sores, so they could only ingest parasites in the
circulating blood. Here again it was unfortunate that, except for one tube of
bugs, all the rest were mature insects. I decided to dissect 100 adults and to
find out what percentage became infected. The dissections were carried out at
intervals from one to five days after the last feed, and I found four bugs con-
taining parasites, some in an unchanged condition still in leucocytes, and all
the intermediate stages shewing the formation and extrusion of the flagellum
and the multiplication of the resulting flagellates, up to the long mature
forms. The remaining bugs, some 200 in number, were taken to Bombay and
D