260 



THE PATHOGENIC FLAGELLATES 



infected with Try p. indicwn, or Holmes in connection with Tryp. 

 cvansi, are regarded as normal stages in the life history of the 

 organism. From the meagre account of the English observers these 

 appear to be nothing more than the nucleus of the cell with a very 

 small layer of protoplasm about it; in rats they become stored up 

 in the spleen and bone marrow, and the authors believe that they 

 ultimately give rise to adult organisms in much the same way 

 that crithidia or herpetomonas is metamorphosed from the resting 

 stage into a flagellate. Without further evidence such phases may be 

 interpreted as special reactions to abnormal conditions rather than 

 stages in the ordinary life history. 



FIG. 102 



Trypanosoma gambiense; stages in longitudinal division. Original from a 

 preparation by F. W. Baeslack. 



D. Reproduction. Reproduction by division is easily observed 

 in all types of trypanosomes, and seems to follow a similar method 

 throughout, the details varying in some cases. As in herpetomonas, 

 it is inaugurated by the division of the kinetic elements of the cell, the 

 flagellum dividing first, according to some observers (e. g., T. gam- 

 biense, according to Minchin), the kinetonucleus dividing before the 

 nucleus, the latter dividing as does the centronucleus of free flagellates. 

 Abnormal division figures are frequently observed, due to the division 

 of nuclei and the formation of new flagella before the cell body splits. 

 As in spirochetes, the daughter cells in the last stage of division are 

 connected only at one end in this case the anterior or kinetonucleus 



