TRYPANOSOMIASIS 369 
Animal trypanosomiasis is also apparently rare in Liberia. We were not able 
to make extensive blood examinations on account of the very few horses and 
relative scarcity of cattle and wild game in the country. However, in none of the 
animals (horses, cattle, and small wild game) examined, were trypanosomes 
found. 
Bouet ' who has investigated the subject of trypanosomiasis of animals in 
the territory of the lower Ivory Coast adjacent to Liberia, found cattle, sheep, 
goats, pigs, and dogs infected. The trypanosome which was regarded as 7’. 
dimorphon was common in cattle, fairly common in dogs and pigs, but rare in 
sheep and goats. He was able to infect monkeys with this trypanosome, and to 
transmit the infection in one experiment to a dog by means of Glossina palpalis. 
Observations in the Congo. While trypanosomiasis is so rare in Liberia, 
numerous opportunities to observe the disease were found during the Expedition 
in the Congo, particularly about Kinshasa and Leopoldville, through the courtesy 
of Dr. Van den Branden, Dr. Duren and Dr. Mouchet; about Brazzaville, 
through the courtesy of Dr. Ledentu; about Tshumbiri, through the courtesy 
of Mr. and Mrs. Paul Metzger; about Coquilhatville, through the courtesy of 
Dr. Strada; about Stanleyville and Yakusu, through the courtesy of Drs. 
Donadio, Chesterman, and Todd. In the Semliki Valley and at New Beni, 
cases of the disease were also observed. Finally, through the courtesy of Dr. 
Duke, we had the opportunity to visit and meet the other members of the League 
of Nations International Commission on Human Trypanosomiasis at Entebbe. 
The excellent studies and reports which have been issued recently by this Com- 
mission have added particularly to our knowledge of this distressing disease,® 
although some of their recent studies upon sleeping sickness do not yet appear 
to have become widely known. 
Differentiation of Trypanosomes. In all of our textbooks of tropical medicine, 
and in the latest work published on protozoology by Wenyon, as well as in Rogers’ 
new book published in 1928 on recent advances in tropical medicine, two varieties 
of sleeping sickness in man are described. The first is said to be due to Trypano- 
soma gambiense and transmitted through the bites of the tsetse fly, Glossina 
palpalis. The second is described as a more acute and deadly type produced by 
Trypanosoma rhodesiense and transmitted by the bites of Glossina morsitans. 
However, it seems to be questionable whether there really are two distinct human 
trypanosomes transmitted by different species of tsetse flies. The Trypanosoma 
rhodesiense of the more virulent disease has been said to be distinguishable from 
T. gambiense by the fact that it produced posterior nuclear forms when inoculated 
into small laboratory animals, while 7’. gambiense did not do so. However, such 
morphological differences have not been substantiated and the posterior nuclear 
forms may be sometimes observed in either Trypanosoma rhodesiense or T. 
gambiense. Indeed these posterior nuclear forms apparently result particularly 
from very rapid multiplication of the trypanosomes in the blood and hence vary 
1 Bouet: Ann. Inst. Pasteur (1907), X XI, 468-474, 969-982. 
2 Mr. Metzger himself had suffered from trypanosomiasis and been successfully treated for it. 
3 Duke, Kleine, Lavier, Prates, Peruzzi, and Van Hoof: Final Report of League of Nations Inter- 
national Commission on Human Trypanosomiasis. Geneva (1928). 
