158 Messrs. H. S. Stannus and W. Yorke. Pathoq'e nic [May 3, 



normal at fairly regular intervals. Although no careful enumeration of 

 trypanosomes was made, yet their numbers were noticed to exhibit a 

 periodicity corresponding to the temperature curve, rises in temperature 

 being associated with increase in the number of trypanosomes in the 

 peripheral blood. 



Morphological Features of the Parasite in the Blood of the Patient. — 

 Unfortunately, the material at our disposal was rather limited, consisting of 

 a slide of the blood made on August 31, the day on which the disease was 

 first diagnosed, a couple of slides made on November 21, and one on 

 January 4, when the patient passed through Zomba on his way to Chinde. 

 The slide made on August 31 contained numerous trypanosomes, and was 

 sent to the Sleeping Sickness Bureau and examined by Sir David Bruce, 

 who found that the parasite did not differ in any way from the Uganda 

 T. gambiense* 



In the specimens prepared on November 20 and January 4, trypanosomes 

 were more scanty and the parasite could not be distinguished from 

 T. gambiense. The parasite presented the characteristic dimorphism, slender 

 forms with long free flagella, short stumpy forms without free flagella, and 

 intermediate forms being found. 



The Morphology of the Parasite in Animals Experimentally Infected. — 

 The parasite was also studied in the blood of several experimental animals. 

 An English rabbit, bred in Nyasaland, was infected with the trypanosome 

 by subcutaneous inoculation with a small quantity of the patient's blood, 

 and, subsequently, sub-inoculations were made into a monkey (Cercopithecus) 

 and a goat. The rabbit and monkey both became heavily infected, and 

 exhibited numerous parasites in the peripheral blood, whereas in the goat 

 trypanosomes were only occasionally found in small numbers. 



Examination of the parasite in the blood of the rabbit and monkey at 

 once revealed the same morphological peculiarity which was observed by 

 Stephens and Fantham in the trypanosome obtained from a case of Sleeping 

 Sickness contracted in the Luangwa Valley of North-East Bhodesia, i.e., 

 among the stout and stumpy forms, some had the nucleus at the posterior 

 (non-flagellar) end (Plate 2, figs. 5-12 and 14-17). When the parasites were 

 numerous, it was found that these posterior nuclear varieties formed from 

 1 to 4 per cent, of the total number of trypanosomes present. Posterior 

 nuclear forms were only observed when the blood contained fairly numerous 

 parasites. They measured 17-22 fi long. 



The other parasites found were indistinguishable from T. gambiense, and 

 exhibited the usual dimorphism. The cytoplasm of many of the parasites 

 * ' Sleeping Sickness Bulletin,' 1910, vol. 2, No. 21, p. 346. 



