44 THE BACTERIA IN ASIATIC CHOLERA. [CH. 



presence of these forms, for I shall show below that the age 

 of a culture has also something to do with it. 



All comma-bacilli when examined fresh show a rapid 

 rotatory movement ; this is obviously the more pronounced 

 the more curved they are ; it is very characteristic in the 

 " dumb-bells," in which the two elements are so arranged 

 that their curvature is directed in opposite ways, and in the 

 chains of close or open spirals. The dumb-bells just 

 mentioned are the result of the successive division of a 

 comma-bacillus ; they are generally S- sna P e d and are very 

 characteristic and generally present along with the single 

 commas. But some dumb-bells also occur in which the two 

 elements are curved in the same direction, being more of the 

 shape of -^'~\ the figure of a flying bird. In the fresh stools 

 and fresh mucus-flakes chains longer than dumb-bells are 

 not frequent, although, as mentioned above, they do occur 

 isolated, and then chiefly in fresh specimens ; in dried and 

 stained specimens they are absent, evidently owing to the 

 facility with which they are broken up into single elements 

 and g-shaped forms during the act of preparation. Of these 

 chains and spirals more will be said below. 



The single elements are rounded at their ends ; in some 

 cases, however, a slight thinning at the ends can be made 

 out with very high powers, such as a -f^ oil-immersion. 

 In dried and stained specimens the comma-bacilli of the 

 stools and intestinal contents appear uniformly stained, but 

 on careful washing after staining, it can be shown that they 

 consist of a delicate sheath with protoplasmic contents. One 

 peculiarity the comma-bacilli possess is that the stain is easily 

 taken out of them by alcohol, more easily than is the case 

 with many other bacteria. On spreading out on a cover- 

 glass a thin film of the mucus- flakes of the ileum, or of a rice- 

 water stool, drying well over the open flame, then staining it 



