414 



NA TURE 



[September 3, 1908 



Now this is a short summary of the discovery of 

 the cause of the "tsetse-fly disease," and one point 

 1 want to bring out is that at that time, and for 

 some time after, there was supposed to be only one 

 ■■ tsetse-fly disease " and one species of tsetse fly. 

 The disease was called " the fly disease," and the My 

 " the tsetse fly." Now all this is changed, and " the 

 flv disease " is now a generic term for several diseases, 

 and the tsetse flies are found to be made up of several 

 more or less well-marked species. 



But the taking for granted that there was only one 

 tsetse-fly disease of course led to much contusion 

 and many mistakes. For example, when Koch 

 studied the fly disease in German East Africa in 1898, 

 naturally he considered he was dealing with the Zulu- 

 land disease, nagana. But was he? Lately, I have 

 studied a trypanosome from the East Coast which 

 causes a more or less mild disease in horses and other 

 animals. Is it not possible that Koch was dealine 

 with this East Coast species when he said that Masai 

 donkeys were not susceptible to nagana? So it can 

 be easily understood how a great number of erroneous 

 notions have crept into the literature of this subject. 



It is evident that what is true of nagana, the 

 disease caused by Trypanosoma hrucei, need not be 

 true of the diseases caused by Trypanosoma theileri, 

 dimorphon, pecandi, congoleiise, vivax, nanum, &c. 

 But an observer conies in contact with one of these 

 diseases in a place where there is no big game and 

 no tsetse fly, and he at once thinks that " the fly 

 disease " does not depend on big game or tsetse flies. 

 When I say that " the tsetse fly " disappears from a 

 district when the big game are killed ofl, and with the 

 extinction of the big game that " the fly disease " also 

 disappears, I only mean that Glossina morsitans dis- 

 appears, and that a particular " fly disease "• — that 

 called by me nagana, and caused by Trypanosoma 

 hrucei — becomes extinct. I do not mean that the 

 diseases caused by Trypanosoma dimorphon, Sec, will 

 be blotted out by the same means. 



With the exception of nagana and sleeping sickness 

 there is little real knowledge as to how the other 

 African trypanosome diseases are spread. That they 

 may spread by other agencies than tsetse flies is prob- 

 able, since surra spreads in India, although there are 

 no tsetse flies in that country. It is quite possible 

 that many of these diseases in Central Africa may 

 not be spread by the agency of tsetse flies and may 

 not depend on the big game as a reservoir of the 

 virus. The cattle themselves may be the reservoir, 

 and the disease may be spread in the herd by means of 

 any of the common biting flies, such as stomoxys or 

 tabanus. In sleeping sickness, so far as we know, 

 the native himself is the reservoir of the disease. 



It is therefore, in my opinion, very important that, 

 in the first place, these trypanosome diseases should 

 be more thoroughly studied as to their distribution, 

 their carrying agent, and the reservoir of the virus. 

 When this is done it may well be that, by the use of 

 this knowledge alone, owners of stock may escape 

 damage. Now that we know the natural history of 

 sleeping sickness, its distribution, its carrying agent, 

 &c., any intelligent person has only himself to blame 

 if he contracts it. 



These few sentences will show how complicated a 

 subject " the fly disease " has become, and in what a 

 state of confusion and chaos the classification of this 

 family of diseases at present is. 



Lastly, in regard to the suggested destruction of 

 big game. To begin with, it may be said that civilis- 

 ation and big game cannot exist together. As soon 

 as a new country is divided off into farms, either for 

 agricultural or stock purposes, the great mass of the 

 wild animals must go. Take, for example, the 



NO. 2027, VOL. 78] 



destruction of the fences by stampeding herds of 

 zebra, wildebeeste, or buffalo, not to speak of the 

 probability that there is not enough food to go round. 

 Even in exceptional cases, where the wild animal has 

 been protected from sentimental and picturesque 

 reasons, as in the case of the herd of hippopotami 

 preserved until lately in Natal, a time came when 

 the neighbouring farmers could no longer put up with 

 their destructive habits, and they had to be destroyed. 

 We may say, then, that when a country becomes 

 settled and civilised, the big game go. This has 

 occurred in Cape Colony, the Orange River Colony, 

 Transvaal, and Natal, and will occur in Zululand 

 when that country is opened up. 



But this inevitable disappearance of wild animals 

 before the advance of civilisation is very different from 

 the instant carrying into effect of an international 

 measure for the wholesale destruction of big game 

 all over Africa. Such a measure, in the present state; 

 of our knowledge, would be quite unjustifiable, and 

 would probably fail to a great extent in its object. 

 Fcstina lentc. Let local authorities frame regulations 

 from time to time as the exigencies of the place 

 demand. But there ought to be room for the next 

 thousand years in many parts of .Africa for game 

 reserves in which all the varieties of big game may 

 live, thereby gladdening the eye and enriching the 

 imagination and fancy of many future generations, 

 and delaying the day when man will have for his sole 

 companions the domestic hen, the cow, and the motor. 



David Brlce. 



THE LATE HENRI BECOUEREL. 



ON Tuesday, .'\ugust 25, 1908, died suddenly Antoine 

 Henri Becquerel at Croisic, in Brittany, at the 

 comparatively early age of fifty-six. 



Henri Becquerel was the third of the scientific 

 dynasty of that name. His grandfather, Antoine 

 C^sar Becquerel (1788-1878), a contemporary of 

 Faraday, was a most prolific investigator of electrical 

 and electrochemical phenomena. He was for forty-nine 

 years a member of the -Xcademy of Sciences, and from 

 1837 until 1878 professor of physics at the Musee 

 d'Histoire naturelle in Paris. The second Becquerel, 

 .Alexandre Edmond (1820-1891), who is known chiefly 

 for his researches in phosphorescence, which are em- 

 bodied in the two volumes of his book" LaLumiere," 

 also made important investigations on thermo- 

 electricity and on underground temperatures. He 

 was professor at the Conservatoire des Arts et 

 Metiers, and succeeded his father as professor and 

 administrator of the Musee d'Histoire naturelle. 



Into this distinguished family Henri Becquerel was 

 born on December 15, 1852. He was educated first 

 at the Lycte Louis le Grand, and at the age of twenty 

 entered the Ecole polytechnique. In 1875 he entered 

 the service of the French Government as an 

 Ingenieur des Fonts et Chausst^es. Three years later, 

 on the death of his grandfather, when his father suc- 

 ceeded to the full professorship at the Muste 

 d'Histoire naturelle (the duties of which he had dis- 

 charged for some years), young Becquerel was ap- 

 pointed his assistant under the title of " Aide- 

 naturaliste. " 



.Already Henri Becquerel had begun to show his 

 powers in original research. The Comptcs rcndiis 

 for 1S75 and 1876 contain his earliest papers, re- 

 searches on magnetic rotatory polarisation. These 

 were continued in 1876 in the Journal dc Pliysique; 

 while in a fourth memoir he discussed the effect on 

 the phenomenon of using different wave-lengths. In 

 1S7S he announced the discovery of the magnetic 



