THE H^MOFLAGELLATES. 319 



(fig. 65^), and even divide again while so united [c£. Try- 

 panosoma ziemanni]. 



So far these authors have been also unable to discern an 

 undulating-membrane. They have observed, however, cer- 

 tain other interesting details of minute structure. In the 

 most successful preparations of spirochEetiform parasites the 

 body appears almost severed in two near the middle, this 

 being due to the occurrence of a small oval clear area (fig. 

 65 a, c, and d). This structure is regarded as the nucleus, 

 apparently very poor in chromatin, and resembling an empty 

 space; K. and S. compai*e it with the nucleus of a Coccidian, 

 where the chromatin is contained mostly in the karyosome 

 and the nuclear membrane. 



In grave or neglected syphilitic lesions forms were en- 

 countered which resembled the contracted spirals, but which 

 were relatively wider and more fusiform. In these indi- 

 viduals (fig. 65 e) one end of the body is drawn out as a long 

 fine filament, while the other is short and sharply conical. In 

 a varying position between the latter extremity and the middle 

 of the body lies the relatively large ovoid vesicle, with well- 

 defined contours, which is considered to be the nucleus. At 

 one side of the nucleus is a distinct, deeply-staining grain or 

 corpuscle. The whole of the body stains uniformly, but, 

 nevertheless, in large " Spirilla," a deeply-staining filament 

 can be recognised, starting at the corpuscle just alluded to, 

 and running superficially in a somewhat sinuous manner 

 (cf. fig.). This structure is regarded by the authors as 

 entirely comparable with the flagellar border of the undu- 

 lating-membrane of a Trypanosome, the corpuscle represent- 

 ing a kinetonucleus. 



From these facts K. and S. conclude that, at certain periods 

 of its existence, Spironema pallidum possesses a try- 

 paniform phase. They consider that the " Trypanosome- 

 forms " result from the growth of the spirochsetiform parasites 

 (in the retracted condition). Probably all the organellae 

 visible in the trypaniform phase are also present in the spiro- 

 cheetiform one, although mostly too fine to discern and study 



