THE HtEMOFLAGELLATES. 265 



(kiuetonuclear element) was situated, and tlie author mentions 

 that he was occasionally able to trace a connection between 

 the two. From the figures it certainly appears as if the para- 

 sites by successive divisions, became more fusiform and less 

 pear-shaped, that seen at g, being, perhaps, derived from 

 a form like that of /, which is in the act of dividing. 

 Even in the most slender and Trypanosome-like stage ob- 

 served, however, Rogers could not distinguish any indications 

 of an undulating membrane, and the kinetonucleus was never 

 far from the insertion of the flagellnm. 



These results have since been fully corroborated by Chatterjee (122), 

 Christophers (123 [3rd Rep.]), and Leisbman and Statham (131). The 

 general appearance of the Flagellate stages figured by these workers quite 

 agrees with that seen in fig. 37 IV, /. and g. Leisbman and Statham bring 

 forward interesting additional observations, and tbe illustrations given are 

 particularly good. The cytoplasm of the parasites is usually very vacuolated ; 

 this is most probably due to the effects of tbe artificial medium upon tbe 

 metabolism. Leisbman and Statham (and also Christophers) describe the 

 actual formation of tbe flagellum, wbicb is developed very suddenly, in a 

 remarkable manner, from a distinctive, vacuole-like structure, termed tbe 

 " flagellar vacuole " ; this arises at the anterior (?) end, in close connection 

 with tbe kinetonucleus (" micronucleus"). Some of tbe contents of this 

 vacuole are expelled to tbe exterior in tbe form of a tuft or brancbed 

 process, and, at tbe same time, tbe flagellum appears. At present it seems 

 impossible to say exactly wbat occurs. Another remarkable process de- 

 scribed is unequal longitudinal fission. Very tbin, sickle-like ("spirillar") 

 portions of tbe body are split ofE from one side of the parent-individual. 

 More than one thread-like form may be thus separated off. The strange 

 feature about the process is that neither of the two principal nuclear 

 elements appears to be concerned. In a few of the parasites chromatin 

 grains are noticeable in tbe cytoplasm, and in one of tbe peculiar fission- 

 forms two of these grains are contained in tbe portion being cut off. 

 Whether these would become the definitive nuclear organella of tbe daughter- 

 parasite is not certain. Anyhow, later on, when the sickle-like form has 

 developed a flagellum, two chromatic elements are present, apparently 

 corresponding to those in tbe ordinary (adult) forms. 



All these accounts agree with that of Rogers with regard 

 to the entire absence of an undulating-membrane. 



Nevertheless, bearing in mind the fact that cultural forms 

 of many Trypanosomes have either a very small membrane 



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