SYNGAMY 339 



described for Leishmanin donovani by Mackie (1915ffl), and for T. cruzi 

 by Hartmann (1917), but in both these cases the descriptions are not 

 convincing, for it would appear from the figures produced that the 

 so-called schizonts are merely the broken-of! portions of the cytoplasm 

 of large cells enclosing leishmania which, as a result of degeneration or 

 feeble staining, have their outlines imperfectly defined, so that the appear- 

 ance of cytoplasmic bodies containing many pairs of nuclei and kineto- 

 plasts is produced. It must be remembered that simple binary fission 

 is the normal method of reproduction, and the multiple segmentation 

 often termed schizogony merely represents retarded division of the cyto- 

 plasm, and is not to be compared with the true schizogony which occurs 

 in the Sporozoa as the normal method of multiplication. 



Mention must be made of another type of reproduction which has been 

 described in only one instance. This is the so-called internal budding 

 noted by McCulloch (1919) as occurring in Crithidia euryophthalmi (Figs. 

 162 and 168). In this process, repeated division of the nucleus is supposed 

 to take place till the posterior region of the body contains a varying 

 number of separate nuclei. Around each a portion of cytoplasm becomes 

 concentrated, while a kinetoplast is formed from the nucleus. The 

 original flagellum, together with the axoneme and kinetoplast, degenerates. 

 There is thus formed an elongated cytoplasmic body in which are em- 

 bedded a number of leishmania forms. Presumably by rupture of the 

 cytoplasm of the original parent, these escape and produce the crithidia 

 forms again. This is a remarkable process which has not hitherto been 

 observed. The figures, which are supposed to illustrate the process, 

 are far from convincing, and suggest the possibility that yeasts or 

 other structures, or even leishmania forms of the flagellate itself, may 

 have been adherent to the surface of the organisms. Minchin and 

 Thomson, J. D. (1915), however, mention certain structures in the cyto- 

 plasm of Lejptomonas pattoni as evidence of a possible endogenous bud 

 formation, a process which they also consider may occur in T. lewisi. 

 They, however, never actually observed the formation of buds, and did 

 not feel justified in describing the process. 



SYNGAMY. 



The possibility of a sexual process occurring in trypanosomes and their 

 allies has attracted considerable attention. Schaudinn (1904) described 

 syngamy in the case of Trypanosoma noctuce, and Prowazek (1904, 1905) 

 in T. lewisi and Herpetomonas muscarum. Various processes of syngamy, 

 parthenogenesis (development of the female gamete without fertilization), 

 and ethiogenesis (development of the male gamete without fertilization), 



