5tO ANNALES DE L'INSTITUT PASTEUR 



formation and extrusion of buds the amœbae multiplied 

 rapidly in the cultures. 



In preserved specimens the body of the amœba was seen 

 to contain a conspicuous principal nucleus (N, fig. 1). vi'^ible 

 in the living condition, and very numerous cliromidial grains 

 in the cytoplasm. In the process of binary fission, the apparent 

 disappearance of the principal nucleus was due to is dividing 

 by mitosis, aft<^r which the cytoplasmic body divided alsi». In 

 the process of bud-formation Ihe principal nucleus took no part; 

 the pi'ocess began by a small porlion of Ihe cytoplasm, contain- 

 ing cliromidia, becoming surrounded by a clear space with 

 fluid contents and thus cut off from the rest ol th • body (iig. 1, 

 A, b). The corpuscle thus defined grew in size, its chromidial 

 grains increased in number, and some of them became dumped 

 together at one spot (Iig. 1, F, b). The entire corpusi-Ie was 

 extruded finally from the bo(!y of the aniœba (fig. 1, (",, h, E) 

 as an amœbula wich contained a nucleus formed fiom the 

 clump of chromidia. In some cases the nucleus was coiupleiely 

 formed before the bud was extruded (iig. 1, !), b): in other 

 cases the bud might be set free with its nucleus scarcely 

 advanced beyond the condition of a clump of chromidia 

 (fig. 1, E, N). Several of these endogenous buds could be 

 observed frequently in piocess of formation in one ami the 

 same amœba. 



If v/e now compare the process described by Fry and Itanken 

 in trvpanosomes with that described in amœbaî by Liston and 

 Martin, I think no one can fail to be struck by their ess^nlial 

 similarity. The bud-formation in trypauosomes begins with 

 extrusion of small chromatin-grains from the trophonucleus 

 (fig. 2, A, chr.), grains which arc proved, both by their origin 

 and desliuy, to be true chromidia. The chromidial mas-es 

 can {je seen in many cases to be cut olf from the cytopiasm of 

 the parent by a clear space; they travel to thi- surface « f ihe 

 body and are cast olf from it as a free bud, which grows in size 

 and develops into a trypanosome (Iig. 2, E-L). In Ihe proi ess 

 of development the bud grows in size by increase of the chro- 

 matin-grains (E) and formation of a cytoplasmic iody (K) 

 while at Ihe same time the dilferentiation of ihe chroinaiin- 

 elements into trophonucleus and kinetonucleus becomes appa- 



