258 THE PATHOGENIC FLAGELLATES 



recognized only when agglomerated or when in motion" (1904, p. 

 432). The majority of observers have confirmed this observation, 

 although in no form are the extremes so far apart as in this case. 

 Minchin ('08) finds the greatest variety of form changes in Tryp. 

 gambiense in the body of the tsetse fly, Glossina palpal is. Here, during 

 the first twenty-four hours, the trypanosomes multiply by division in 

 the fly's digestive tract, two distinct types being formed, one stout, the 

 other slender. During the next twenty-four hours the two types are 

 connected by all kinds of intermediate forms, which in the third day 

 become thinned out and presenting some degeneration forms, and 

 many trypanosomes of great length, both stout and slender; while 

 after the fourth day no organisms were found at all. Similarly Tryp. 

 grayi was found in the digestive tract of the same fly to manifest the 

 most "bewildering variety of forms and sizes," while in different flies 

 the run of organisms might be much larger than in others. Division, 

 also, is responsible for variation in size, Minchin finding that smaller 

 daughter trypanosomes are formed by unequal division of the parent 

 cell. 



Following Schaudinn, many, indeed the majority of, observers have 

 attempted to distinguish these manifold form changes as male, female, 

 and indifferent types. While some of their descriptions are mani- 

 festly labored and far-fetched, others are supported by more or less con- 

 vincing evidence. In the type form Tryp. noctuce the chief differences 

 are found in the nuclei, where, as described above, the male and female 

 organisms are freed from female and male chromatin respectively 

 (Figs. 99 and 101 ). In addition to this difference, Schaudinn noted that 

 the male cells were hyaline and more free from granules of one kind 

 or another than the female, while the indifferent forms were dis- 

 tinguished from both of the other types by the complete nucleus 

 and by minor cytoplasmic differences. It must be confessed that, 

 despite the scientific acumen of this observer, one's credulity is greatly 

 stretched by these findings, and in view of the fact that so much of the 

 subsequent work has been interpreted in terms of these descriptions, 

 it is much to be regretted that Schaudinn's figures were wholly 

 schematic. Prowazek ('05) found only a slight difference between 

 the sexes in Tryp. lewisi while in the gut of the louse, the male 

 being smaller and more fragile than the female and much more 

 liable to degenerate, while the nucleus assumes an elongate band 

 form or rod form in the male. These might be identified as 

 degeneration forms were one inclined to be skeptical, especially as 

 fertilization stages were rarely seen; the "rod" form of nucleus, as 

 Doflein ('09) points out, may be interpreted as an abnormally devel- 

 oped flagellum. 



Moore and Breinl ('07) question the advisability of designating 

 arbitrarily chosen extremes in a series of varying forms as male and 



