No. 49S] 



THE SPIROCHETES 



383 



posed to those of Novy and Knapp with regard to the 

 structure and relations of the spirochetes. It should be 

 remembered that the species (S. gallinarum) on which 

 Prowazek worked was one of those which Novy regarded 

 as most positively of plant affinities. On the basis of 

 most critical observations Prowazek indicates the pres- 

 ence of an undulating membrane with a conspicuous 

 marginal cord. The body of this spirochete he finds to be 

 flexible, a feature emphasized by various authors in the 

 diagnosis of the genus. An analysis of the various types 

 of movement shows, in his opinion, marked similarity to 

 organisms possessing an undulating membrane or to the 

 similarly provided sperm cells. Distinct granules lie in 

 the axis of the organism which do not constitute a definite 

 nucleus in the general sense of the term, but form 

 chromidia such as are well known to occur frequently in 

 the protozoon cell in the place of a single circumscribed 

 nucleus. 



So far as the conduct of these spirochetes towards 

 reagents is concerned, the use of salt solutions did not 

 produce the plasmolysis characteristic for bacteria even 

 though the solutions were stronger than those sometimes 

 successful in effecting this among the bacteria. Dilute 

 alkaline solutions affected the spirochetes wliereas the 

 bacteria are very resistant towards them. 



The identification and interpretation of the method of 

 division is believed to be of especial importance in de- 

 termining the systematic position of the spirochetes. In 

 the opinion of Prowazek transverse division may occur, 

 yet positive evidence demonstrated the occurrence of 

 longitudinal division. Similar conditions in part were 

 found on the species from the mouth (8. dent htm) and 

 were especially clearly illustrated by the observations of 

 Keysselitz on a spirochete obtained from the fresh water 



of that process which was clearly longitudinal could be 



