GENERAL CHARACTERS OF SPIROCH.ETES. 71 



4. Spirillum, Ehr., 1833. Spiral, cylindrical or- 

 ganisms ; blunt ends ; no undulating membrane ; 

 spores ; terminal flagella (many species) . 



B. TRYPANOSOMID^:. Doflein, 1901. Flagel- 

 lated; flexible; undulating membrane; longitudinal 

 division; not cultivable. 



1. Spirochata, Ehrenberg, 1833. (Spirochaete, Cohn, 

 1 83 5 .) Thin, spiral ; flattened ; undulating mem- 

 brane; no flagella; filiform nucleus and chro- 

 matin granules (type, Sp. plicatilis). 



2. Treponema, Schaudinn, 1905. (Spironema, 

 Vuillemin, 1905). Characters as stated above. 

 (Trep. pallidum.) 



3. Trypanosoma, Gruby, 1844. 



Liihe divides spirochaetes into : 



1. True spirochsetes, including Sp. plicatilis, bal- 

 bianii, buccalis, dentium, vincenti, vaccines, 

 refringens, pseudo-pallida, and the spirochaete 

 of dysentery. 



2. Blood-spirochaetes, including Sp. gallinarum, 

 anserina, obermeieri, duttoni, theileri. 



3 . Treponema : Tr. pallidum and pertenue. 



Gross who believes that spirochaetes are closely allied 

 to the bacteria, coins a new name for the whole genus, 

 Cristispira, derived from the crest or ridge which he 

 believes to run along one side of the body or around it 

 (this formation having given rise to the statement that 

 spirochaetes possess an undulating membrane). 



