176 MICRO-ORGANISMS AND DISEASE. [CHAP. 



considerable limits, some being just curved while others are 

 almost semicircular, some being twice and three times as 

 long as others. They are motile, and divide transversely. 

 In neutral Agar-Agar mixture, kept at ordinary temperature, 

 length-divisions may be observed (see Fig. 98). After trans- 

 verse division they may remain joined end to end, and then 

 forming an S-shaped corpuscle. But sometimes, particularly 

 in artificial cultivations in broth, they remain joined end to 

 end even after repeated division, and then form either a 



FIG. 97. 



From an Artificial Cultivation of chole- 

 raic Comma-bacilli in Gelatine 

 Peptone. Magnifying power 700. 

 Most of these are single curved 

 bacteria, a few are joined end to 

 end in twos, thus forming S-shaped 

 organisms ; and a few are in chains 

 of several placed end to end. 



O 



A* 



: *i 



FIG. 98. 



From an Artificial Cultivation of chole- 

 raic Comma-bacilli in Agar-Agar 

 Peptone at the ordinary tempera- 

 ture of the room after several 

 weeks. The Comma-bacilli change 

 by vacuolation into planoconvex, 

 then biconvex, and finally circular 

 organisms ; these by division give 

 origin to two semicircular comma- 

 bacilli. Magnifying power about 

 700. 



wavy or spiral-like organism. But the type is represented 

 by a single curved rod. For this reason it is not correct 

 to speak of them as comma-bacill, since they correspond to 

 what is generally considered a vibrio or spirillum. 



The comma-bacilli are present, amongst crowds of other 

 putrefactive bacteria, in very varying numbers in the choleraic 

 evacuations, sometimes very scarce, sometimes numerous ; in 

 the mucus-flakes taken from the cavity of the lower part of 

 the ileum of typical rapidly fatal cases of cholera very soon 



