Minutes of evidence taken by the Departmental Committee on Sleeping Sickness.
- Great Britain. Colonial Office. Committee on Sleeping Sickness.
- Date:
- 1914
Licence: Public Domain Mark
Credit: Minutes of evidence taken by the Departmental Committee on Sleeping Sickness. Source: Wellcome Collection.
18/346 (page 8)
![10 October 1913.] [ Continued. “The fly has come back; the big game are getting more numerous.” But that to my mind is not very good evidence, as it depends on the magistrate, he might be a man who told fairy tales, or he might be a man too idle to send a native down to the fly country to see if there were flies there in the particular year, but I give it for what it is worth. With regard to Nyasaland in the same way, in this country here there was no fly up to a few years ago. When the rinderpest passed through in or about the year 1895 it killed off most of the big game, and at that time (this is the report of the white people, missionaries, and others who knew the country) the fly disappeared out of the whole of this fly country, but remained at a spot near the south of the lake, and it was known they were there. I have a map of Nyasaland here which may be useful; this is only a map of a small part. Here is Domira Bay; it was down south of the lake that the fly remained. There were thousands of cattle all over this country a few years ago, that is to say, eight or ten years ago. There was a man here at Lingadzi who had large numbers of cattle, and he had them round Domira Bay and all over the country. There were no deaths among them at all until suddenly they began to die, and he was forced to take them out of the country altogether in order to save further mortality. This is said by certain people to have been due to the fact of rinderpest passing through this country about 1895, it being 10 years before the fly again spread over this area. There can be no doubt that this is typical fly country, and has been from time immemorial. 122. I think in Africa in some of those areas here it is almost the unanimous belief of farmers that you cannot stock-farm in a place where big game is kept; do you agree with that ?—In a country where there is no fly the wild animals would naturally damage the stock farmer by eating up the food his own stock ought to get, or by destroying his fences. 123. I refer to the fly country particularly >—In the fly country the farmer could not keep stock at all. 124. (Mr. Austen.) At the risk of increasing Sir David Bruce’s disdain for i very fond of them. The entomologists say, and go on saying, “‘ We want to find out more about the biono- mics of the tsetse-fly ’; you can say that for 20 years and in the meantime nothing is being done, and I have only a few more years to live myself. 125. I can assure Sir David that the entomologists are as anxious as he is to find out the real remedy. I would like to ask two entomological questions, and also two others. When this new trypanosome was dis- covered in North-Eastern Rhodesia and in Nyasaland, certain structural peculiarities were noticed init which led people in the first place to think they were dealing with a new parasite. Subsequently, those peculiarities were re-considered; they were found elsewhere, and Sir David Bruce came to the conclusion that this try- panosome was nothing but Trypanosoma brucei which he himself had discovered in Zululand in 1894-7, and that it was disseminated by the same fly. I see he says here on page 2 in the first section of his evidence that, “It was proved at that time ”’ (that is in the nineties) “and « for the first time that these parasites were carried “ from sick to healthy animals by the local tsetse-fly «“ Glossina morsitans.” I should like to ask whether the figures you yourself published at the time did not show, “and whether the specimens you sent from Zulu- land also did not show that the fly you had to deal with then was not Glossina morsitans at all but a totally different species known as_ Glossina pallidipes ?— There is no doubt that the evidence is that the tsetse fly we were dealing with in Zululand was Glossina pallidipes. I look on Glossina pallidipes and Glossina morsitans as being very closely related. They have the same habits, they inhabit the same country and live among the wild game in the same way, so that I look on the two as being very closely related, and you can call them one for practical purposes. 126, But the structural differences between them are at least as great and, I think, I might call them con- siderably greater than the structural differences between two so-called species of trypanogomes. I think you admit that?—That is your trade, it is not mine. I know they are very nearly the same size and live in the same kind of country and have the same habits, and I am perfectly certain the trypanosomes develop in the interior of pallidipes in the same way as in the interior of morsitans and that is sufficient for me. 127. That is not doubted. I think I may take it that this is a misprint here on the second page of your statement ’—Yes, that word “ morsitans”’ is meant to include pallidipes. We find that even in brevipalpis, which is a very different kind of fly from morsitans or pallidipes, the same development goes on of the Tiry- panosoma brucei vel rhodesiense as in morsitans. 128. Recent results have shown that whereas we used to think that all tsetse-flies had the same habits we know now, in certain cases at any rate, that the habits of different species of tsetse-flies are very markedly different, and therefore I think when we mean one particular species we must now be careful to call it by its right name; it may have a practical bearing >—Yes, but in this particular case I think these two species—morsitans and pallidipes—are very much the same in habits and habitat. I was talking about palpalis, which have very different habits, and T would differentiate strictly between palpalis and morsitans. 129. They eleue to totally different groups, of course. My second question has reference to the statement in Part V. of your evidence as to the great powers of flight of the fly. Sir David Bruce says that morsitans can possibly fly a mile a minute, but I humbly beg to doubt that; certainly no one will deny that, if we have a deadly fly such as this tearing about Africa at the speed of an express train, the question is far more serious even than we now think it is, and when this particular fly is said to overtake a motor-cycle going at 30 miles an hour, I should like to ask how much start the motor-cycle had ?—It is quite possible that the fly can fly at the rate of a mile a minute, but it does not do it, because it does not want to do it; it does not come into its particular habit of life. I can run at five miles an hour, but I never do it if I can possibly help it. 130. Erroneous impressions get abroad on very slight foundations, and I think we ought to clear up the point as regards how much start the motor-cyclist had. I doubt whether there is a fly in existence which can fly at 60 miles an hour for any distance atall. It is admitted that the faster an ordinary cyclist goes the more flies will follow him, not only Glossina morsitans but palpalis too ?—Yes. 131. How did you time them?—We had not a starter. 132. Do you mean to say that a cyclist going at 30 miles an hour actually passed a point and got a good way beyond it, and that the fly started from that point and caught him up ’—What I mean is that when you are going along at a great rate the flies are passing over your head and seem to be in front of you at one minute and behind at another, and they seem to alight on you as they like, you knock them off, and they come buzzing on to youagain. ‘hey seem to me to have command of the situation, you can call it 60 miles an hour or 100 miles an hour, but all I say is that they are very rapid on the wing. 133. I might suggest that a cyclist going at a rapid speed through the air forms a partial vacuum in the air, and diminishes the air resistance for any insects which may be about him or following him, and there- fore in your view he renders it much easier for the fly to travel over the ground at a rapid pace than if there were no cyclist at all >—We are pacemakers, in fact. 154, Yes, if you like, and you facilitate the passage of the fly, you would admit that ?—I admit that. 135. Inotice in Part IT. of your evidence, in referring to Dr. Taute’s experiments upon himself, which, of course, all the Committee are familiar with, you say “It isa matter for keen regret that these experiments were not successful.’ Iam not sure that the Committee will agree with that remark, because if they had been successful we should have been mourning the loss of a very able investigator. You say thata negative experi- - ment proves hothing. With regard to that you will admit that Dr. Taute is at issue with you. You have referred](https://iiif.wellcomecollection.org/image/b32178104_0018.jp2/full/800%2C/0/default.jpg)
