42 SPIROCH^ETES. 



ion with Sp. gallinarum (Fig. 51) and with Sp. lutra 

 (see Fig. 71), by Mayer in the blood of a mouse infected 

 with Sp. duttoni (Fig. 52), and by other observers else- 

 where. Loewenthal found rod-shaped and sausage- 



FIG. 50. FIG. 51. 



FIG. 50. Abnormal forms associated with Spirochseta pallida. 

 (Krzystalowicz and Siedlecki.) 

 FIG. 51. Spirochaeta gallinarum and rod forms. (Prowazek.) 



shaped bodies along with spirochaetes in ulcerated 

 cancers. 



Qury believes that Sp. pallida is a stage in the 

 development of a bacillus which he cultivated; from 

 it he prepared a serum which Hallopeau found to have 



FIG. 52. Rod forms (a, c) and Spirochaeta duttoni (6) in blood 

 of mouse. (Mayer.) 



some curative value in syphilis. Von Niessen also 

 holds that the Sp. pallida is a developmental form 

 of a special cocco-bacillus which he obtained in pure 

 culture. 



ASSOCIATION WITH OTHER ORGANISMS. 



The association of spirochaetes with other organisms 

 is of considerable interest as either constituting an 

 example of symbiosis or suggesting the possibility that 



