198 MICROBES, FERMENTS, AND MOULDS. 



are full of motion and activity, which they retain for 

 some time. They are arched in form, and, roughly 

 speaking, resemble a comma. Their length is 1 J micro- 

 millimetres to 2 J micro-millimetres, and their width is 

 0'6 to 07 micro-millimetre. They are often arranged 

 in chains or chaplets, so as to appear like the letter S, 

 or several S's, placed end, to end as we see in Fig. 87. 

 These latter are the most characteristic. Compared 







Fig. 87. Cholera microbe, or Bacillus Tcomma (Koch) : a-e, the different forrrs which 

 it presents in its growth and division into cells (greatly magnified) ; 1, 2, cultures 

 of bacillus, under a simple lens. 



with the microbe of tuberculosis, that of cholera is 

 shorter and thicker. Its spiral shape has led to the 

 belief that it is an intermediate form between the 

 genera Bacillus and Spirillum. 



Comma-shaped microbes may be found in most 

 stagnant and running water, but they are in general 

 much larger, and none of them present the charac- 

 teristic dimensions of Bacillus komma. 



This bacillus is found in the riziform grains of 

 choleraic evacuations, which are, as we know, formed 



