Miscellaneous. 401 



he was of muscular build, with prognathous jaws, a straight thigh, 

 an extremely platycnemic tibia, and a thick dolichocephalic skull. 

 The animal-remains found in the cave-earth of other parts of the 

 Cavern, and held by the Author to be contemporaneous with that 

 in the fissure, are those of mid- and late Pleistocene age ; and this 

 evidence, together with that derived from the position of the skeleton, 

 the shape of the cranium, and the form and workmanship of the 

 flakes, points to a period towards the close of the Palaeolithic or the 

 opening of the Neolithic Age. 



MISCELLANEOUS. 



The Action of Human Serum on certain Pathogenic Tn/panosomes ; 

 Action of Arsenious Acid upon Trypanosoma gambiense. By 

 A. Laveran. 



In previous notes (1st April, 1902, and Gth July, 1903) I have 

 shown that human serum injected in sufficient doses into mice or 

 rats affected with Nagana, Mai de Caderas, or Surra, caused the 

 Trypanosomas to disappear, at least temporarily, from the greater 

 circulation. 



A mouse weighing 20-25 grammes required - 5 to 1 c.c. of 

 human serum ; a rat of 200 grm., 2-3 c.c. of serum or 0-20-0-30 

 grm. of dry serum in powder. 



The Trypanosomes disappear in 24 or 36 hours from the larger 

 circulation, but reappear in general at the end of a few days. 

 Sometimes their disappearance is definitive. The most frequently 

 repeated injections of human serum do nothing more than prolong 

 the life of the animals. 



In the month of November, 1903, Drs. Dutton and Todd sent me 

 through Dr. Annett two rats, one infected with Trypanosoma gam- 

 biense, the other with a Trypanosoma of horses from the Gambia. 

 It appeared demonstrated that Tr. gambiense, discovered by Forde and 

 Dutton in Gambia, is identical with the Trypanosoma described by 

 Castellaini under the name of Tr. ugandense, as the pathogenic 

 agent in the disease called " sleeping sickness." The study of this 

 parasite is therefore, from the medical point of view, of great 

 interest. 



One might think, a priori, that Tr. gambiense, which is developed 

 in the blood of man, as in that of many other mammals, would not 

 be influenced by human serum, contrary to that which takes place 

 in the case of the Trypanosomes of Nagana, Surra, and Caderas, 

 diseases against which man is naturally immune. This is precisely 

 the result of my observations. Human serum injected in doses of 

 0*20-0-30 grm. of the powder, in the case of rats weighing 170 to 

 200 grm. infected with Tr. gambiense, proved entirely inactive. 



At the beginning of the infection of rats with Tr. gambiense, the 

 Trypanosomes are very rare in the blood, and it happens that after 



Ann. & Mag. N. Hist. Ser. 7. Vol. xiii. 27 



