50 THE BACTERIA IN ASIATIC CHOLERA. [CH. 



or vice versa, they change their morphological characters 

 accordingly. I have examined numerous specimens from 

 such a culture-tube of egg-albumen and Agar-agar, after 

 several days' to several weeks' growth at 35-37C., and 

 although there was copious growth present I did not see any 

 spiral forms. The reason is obvious, namely, that since the 

 individual comma-bacilli are almost straight, or at all events 

 only very slightly bent, their chains are more like leptothrix : 

 a spiral can of course only be produced by a chain of 

 well-curved organisms ; and just as a leptothrix is made up 

 of a chain of straight bacilli, so a spiral is one of curved 

 organisms. This holds good also for the S~ sna P e d forms 

 of the comma-bacilli ; in the egg-albumen and Agar-agar 

 mixture there are numerous dumb-bells, but they bear not 

 much resemblance to the typical S~ sna P e d forms of the 

 comma-bacilli, since the elements in the former are more 

 or less straight. 



There can, then, be no doubt about the fact that in the 

 different artificial media the comma-bacilli show distinctions 

 as regards size and curvature. The most striking difference 

 is that shown by comma-bacilli cultivated in an alkaline 

 mixture of egg-albumen and Agar-agar. 



Of very great importance, both from a morphological and 

 from a physiological point of view, in the life-history of all 

 bacterial species, is the question of spore-formation. 

 Hitherto in those species only which are known as bacilli 

 has real spore-formation been observed. In some species 

 of bacillus the single rod or part of a chain or leptothrix- 

 thread is capable of producing at the expense of its 

 protoplasm bright glistening spores, spherical, or more 

 generally oval in shape ; and these spores when fully 

 developed leave the sheath of the bacillus and represent the 

 real seed, for they are capable of retaining vitality for an 



