46 (no) Society for Experimental Biology and Medicine. 



of course, have been derived from the frog from which the blood- 

 agar was made. This frog's blood was examined for parasites 

 before using it to make the medium and just before inoculating 

 it, so that trypanosomes must have been present in numbers too 

 small to show in several large cover-glass preparations, or they 

 existed in some developmental stage not recognized. Novy and 

 MacNeal have also secured cultures of trypanosomes from birds, 

 where none were found by direct examination of the blood with 

 the microscope [page 23 (87)]. 



In some preparations from the blood-agar tubes as many as 

 four trypanosomes appeared in one field (Zeiss, DD., No. 3 ocular), 

 and there can hardly be any doubt of their having multiplied. The 

 motion of the trypanosomes was active and characteristic. They 

 were much smaller than Tr. rotatorium i with rare exceptions, the 

 body being usually about 3/i x 16 /jl. The flagellum was hardly 

 half as long as the body. On the small forms the undulating 

 membrane was not distinct, but the flagellum was plainly marked. 

 Large forms, similar to Tr. rotatorium, except that the flagellum 

 was lacking, occurred, but were rare. The nucleus and blepharo- 

 plast were placed as in Tr. rotatorium, as far as could be deter- 

 mined, but the amount of material was so small that satisfactory, 

 stained preparations could not be secured. 



With the trypanosomes there were associated spindle-shaped 

 or crescentic bodies, about 12// in length, looking much like the 

 crescents of aestivoautumnal malaria, except for lack of pigment. 

 These bodies contained several (usually four) shining chromatin 

 granules symmetrically placed in the middle. Motility was doubt- 

 ful, and in any case slight. Flagella were not seen. The cres- 

 centic forms were probably some developmental stage. The cres- 

 centic bodies were observed for eight weeks. Motile trypanosomes 

 were observed for five weeks. No growth occurred in subcultures. 

 Two frogs were inoculated by way of the peritoneum from tubes 

 containing the crescentic bodies, with negative results. 



3. Attempts to produce development of Drepanidium were 

 made from three frogs infected with this parasite, both on frog's 

 and toad's blood-agar. The results were negative, although motile 

 Drcpanidiavizxz discovered after ten days, and the parasites remained 

 for weeks apparently unaltered within the blood-corpuscles. 



