48 THE BACTERIA IN ASIATIC CHOLERA. [CH. 



curved. By this time there are also present a few long 

 wavy and spiral forms ; these latter increase in numbers as 

 growth proceeds ; the longest spirals, some extending over 

 one-fourth or one-third of the field of the microscope 

 (Zeiss's eye-piece 3, obj. D), I have found in alkaline 

 broth-cultures that had been growing at 35C. for a week. 

 Some of them are spirally twisted, others more wavy, in 

 some one portion is a spiral, while another portion is wavy, 

 or apparently almost straight. In some well-washed stained 

 specimens the individual commas constituting the wavy or 

 spiral form can be recognised, in others there seems no 



FIG. 9. ARTIFICIAL CULTIVATION OF THE SAME COMMA-BACILLI AS IN- 

 PRECEDING FIGURE IN ALKALINE PEPTONE BROTH GELATINE. 



The comma-bacilli are not so large and not so well curved. 

 Magnifying power 700. 



differentiation to be made out. During the drying and 

 staining of the specimens many long spirals break up into 

 short spirals. In cultivations carried on in broth (alkaline) 

 at 35-37C. a pellicle makes its appearance already after 

 36-48 hours, this thickens and becomes more connected as 

 growth proceeds ; this pellicle is made up almost entirely of 

 longer or shorter spirals. 



In Agar-agar mixture, alkaline and neutral (Agar-agar i per 

 cent., peptone i per cent., both dissolved in beef-broth), the 

 comma-bacilli are not so well curved and uniform in size as 

 in gelatine mixture. On growing the comma-bacilli in Agar- 



