368 



when the proportion is i : 2, or even i : 10. T. brucei is much 

 more difficult to grow, the best proportions of blood to agar 

 are 2 : i or 3 : i . 



The culture medium is best poured into flasks so as to get 

 a large but shallow layer of condensation water. After inocu- 

 lation the cultures are kept at a temperature of 25° C. y\s soon 

 as a good growth is obtained subcultures should be made. 

 ,Bacterial contamination must be scrupulously avoided. 



In cultures of T. lewisi forms 1-2 /x (excluding flagellum) 

 in length are found, and filtrates that have passed through a 

 Berkefeld filter are infective, The virulence of cultures may be 

 completely lost, though the trypanosomes are still active and 

 growing in subcultures. 



Genus Trypanoplasma 



1. Trypanoplasma borrelt. — Twenty /« long, 

 three to four m broad. Each flagellum, fifteen fj- 

 long. It is curved in shape. 'The undulating 

 membrane on the convexity. The anterior end 

 is more pointed than the posterior. Found in the 

 blood of the red eye [Leuciscus erythrophthalmus). 

 Also a similar, if not identical, species in min- 

 nows {Phoxinus laevis). They may cause anaemia, 

 wasting, and death of the fish (Fig. 82). 



2. T. cyprini. — In the carp {Cypvinus carpio). 

 Ten to twenty to thirty m long. The flagella are , 

 of unequal length. The anterior flagellum is twice 

 as long as the posterior. Pathogenic (?). 



Addendum. 



T. noctuae {Vide p. 345). — Drs. Ed. and Et. Sergent have 

 confirmed Schaudinn's results. Culex pipiens were fed on an 

 owl containing ' halteridia.' A month later they were allowed 

 to bite on four occasions a non-infected owl. Two days after 

 the last meal, the owl showed ' halteridia ' in its blood. 



1904. 



LITERATURE 

 Trypanosomes et Trypanosomiasis. Laveran and Mesnil. 



