378 



Dr. H. L. Duke. Relation of Fowls and [May 9, 



prunase. This conclusion is perhaps more in harmony with that indicated 

 above that vicianase may be present together with linase. 



Such briefly are the problems before us. It may be that the differences 

 observed are in some cases due to faulty determinations and much remains 

 to be done in establishing valid methods of determining enzymic activity. 

 But differences such as we have referred to are met with so constantly that 

 it is clear that they correspond to actual variations in character and propor- 

 tion of the enzymes present in plants. 



Observations on Fowls and Ducks in Uganda with Relation to 

 Trypanosoma gallmarum and T. gambiense. 

 By Dr. H. L. Duke. (With a Note by Miss Muriel Robertson.) 



(Communicated by Sir J. R. Bradford, K.C.M.G., Sec. R.S. Received May 9 — 

 Read June 6, 1912.) 



[Plate 9.] 



In the course of a considerable number of experiments, carried out to 

 investigate the duration of infectivity of antelopes for T. gambiense, Uganda 

 fowls were employed to nourish the flies during the earlier days of the 

 experiments. The birds have been shown by the Commission of 1908-10 to 

 harbour T. gallinaruni in a certain number of instances, although nothing was 

 known concerning the intermediate host of this trypanosome. 



In the course of routine dissections of laboratory-bred flies from these 

 experiments a curious crithidial type of flagellate was noticed in the hinder 

 part of the mid-gut, similar to that reported recently from this laboratory 

 by Captain A. D. Fraser and myself. These flagellates must have been 

 derived either from the antelope upon which the flies originally fed or from 

 the cock. In morphology and movement they were distinguishable at once 

 from developmental stages of T. gambiense in Glossina palpalis. As some of 

 the laboratory antelope had been found to be infected with T. ingens it 

 appeared possible that the flagellates might represent developmental stages 

 of this trypanosome. On the other hand suspicion fell upon T. gallinaruni, 

 although at the time microscopical examination of the fowls used had always 

 proved negative. 



To solve the point clean laboratory-bred flies were fed upon the suspected 

 cocks, with the result that after two failures the crithidise were obtained in 



