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Chapter XXXI 



SPIROCHAETES 



The Spirilla are distinguished from the spiro- 

 chaetes : (i) by their inflexible body, (2) by the 

 possession of a tuft of terminal flagella, (3) by their 

 having a firm cuticular cell wall, as other bacteria, 

 capable of resisting the action of ten per cent, potash, 

 whereas spirochaetes are completely dissolved. What 

 spirochaetes are, is a matter of great dispute. By some 

 authors they are considered to be flagellates, by others 

 bacteria. 



Spirochaeta. May provisionally be defined as 

 follows : Body not spiral (?) but shewing regular 

 snake-like undulations in the same plane, consisting of 

 sheath or periplast (? undulating membrane) and 

 endoplasm. Division transverse (? also longitudinal), 

 the two separating portions being often joined by a 

 fine thread, the length of the two young individuals 

 being equal to that of the original spirochaete. A 

 terminal appendage (flagellum) can be shewn by special 

 methods, but it may simply be a portion of the above 

 thread or elongated sheath. Bacterium-like flagella 

 exceedingly doubtful. They may be the frayed-out 

 ectoplasmic sheath. 



Encysted Forms. Just before the crisis in the case 

 of Sp. duttoni, Breinl described the formation of cysts in 

 the spleen. The spirochaete becomes rolled up into 

 tangles and is generally eaten up by phagocytes, but 

 some few become encysted, the contents of the cyst 

 breaking up into small granules. It is possibly from 

 these granules that the new generation of spirochaetes 

 develops. 



