110 SPIROCH^TES. 



by Levaditi's method, is shown in figure 88 (see also 

 plate, Fig. B). 



A sexual cycle has been described by Krzystalowicz 

 and Siedlecki. According to these writers, certain 

 spirochaetes become thicker and less sharply curved, 

 and constitute the female gametes. Other individuals 

 are found with many nuclei, and these by fragmentation 

 produce a large number of minute spirillar forms, 

 which are the male gametes (Fig. 38). One of these 

 conjugates with a female gamete, and the individual 



FIG. 88. Spirochaeta pallida in liver of syphilitic foetus stained 

 by Levaditi's silver method. 



thus formed probably enters on a resting stage, which 

 has not been definitely identified. These writers con- 

 sider the Spirochazta pallida to be a trypanosome, and 

 call it Trypanosoma luis. The same view is taken by 

 Leuriaux and v. Geets, who describe oval bodies which 

 elongate and give rise to fine filaments ; these latter are 

 the microgametes (the spirochsetal form), while the 

 female gametes are represented by a tryponosome-like 

 stage. They suggest that the oval forms found by 

 them are identical with Siegel's Cytoryctes luis. 



The observations of Krzystalowicz and Siedlecki 



