TRYPANOSOMES OF AMPHIBIA 595 



repeated till a collection of twenty to thirty-two small cytoplasmic bodies 

 devoid of flagella results. After twenty to twenty-four hours from the 

 commencement the small bodies begin to exhibit trembling movements, 

 and careful observation reveals a short flagellum on each. Division of these 

 forms continues, and they gradually elongate and assume the crithidia 

 form with a short undulating membrane. After forty-eight hours each 

 original trypanosome will have given rise to a cluster made up of about 

 150 small crithidia forms. The clusters then break up, and the individuals 

 swim away and continue their multiplication. It will be noted that the 

 original trypanosome loses its flagellum entirely, and those of the daughter 

 individuals are newly formed. Furthermore, the division is always a 

 repeated simple binary fission, and not a multiple segmentation. Noller 

 was able to make a similar observation on the broad leaf-like trypanosomes 

 (type 3). In the case of these the process proceeds more slowly, and the 

 large cytoplasmic body formed from the original tryj)anosome extrudes a 

 number of bud-like processes representing the daughter individuals, which, 

 however, do not detach themselves. As many as forty-eight may be 

 present after forty-eight hours. After another twenty-four hours flagella 

 develop at the pointed extremities of these processes, and finally a mass of 

 small crithidia forms is produced. They remain grouped together, however, 

 for a much longer time than in the development of the trypanosome of 

 type 2. Noller seems to think that the length of time that these daughter 

 forms remain together in clusters is suggestive of the division having taken 

 place within the periplast of the original trypanosome. It is probable 

 that this development, which takes place in vitro, represents the early 

 development in the leech, Hemiclepsis marginata. Noller believes that 

 the leech, Piscicola geometra, will also prove to be a vector of T. rotatorium. 



Ponselle (19236) has shown that this development of the large trypano- 

 some is directly dependent upon the reaction of the medium. It will not 

 take place in blood mixed with simple saline solution, but occurs if broth 

 is used to dilute the blood. Broth having an acid reaction (about pH 6-3), 

 he tested saline to which 0-2 per cent. HCl was added, and found that the 

 development took place. By substituting a more complex mixture such 

 as Ringer-Locke solution for the simple saline, the development was even 

 quicker. It was found that cultures of T. rotatorium could easily be 

 obtained in a mixture of broth and one-tenth its volume of defibrinated 

 rabbit's blood. No development occurred in a mixture of equal parts of 

 distilled water and defibrinated rabbit's blood. In the case of T. inopi- 

 natum development readily occurred in the latter, but not in the 

 former, so that each mixture appears to be specific for its particular 

 trypanosome. 



Trypanosoma inopinatum Ed. and Et. Sergent, 1904.— This trypano- 



