XVI] VIBRIO AND SPIRILLUM 423 



rapidly motile vibrios, single commas, S-shaped dumb-bells 

 and numerous longer or shorter spirilla, some wavy chains of 

 commas, others uniformly spiral; the above-named "gran- 

 ules" and "flakes" are masses of commas and spirals inti- 

 mately matted together, and when examined in the hanging 

 drop look like so many clumps rapidly revolving. 



In stab culture in gelatine the characters of these comma 

 bacilli are also well marked ; they are accurately repre- 

 sented in Fig. 176, and need not further be described, 

 except that there are considerable differences as regards 

 the rapidity with which the growth causes liquefaction in 

 the gelatine ; in all cases however it starts from the surface. 



After several days to a fortnight there is noticed a dis- 

 tinct pellicle on the surface of the liquefied gelatine in 

 some cases, in others such a pellicle is absent ; the gelatine 

 is Clear, but contains a few whitish granules marking the 

 outline of the funnel-shaped channel of liquefied gelatine. 



Alkahne broth (at 36-38° C.) is slightly turbid already 

 after twenty-four hours' growth : this increases during the 

 succeeding days. After a week or so the superficial layers 

 become gradually clearer, and this extends gradually and 

 insensibly towards the deeper layers ; hand in hand with 

 this goes the deposit of a grayish-white powdery precipi- 

 tate ; a more or less distinct pellicle is noticed already after 

 a few days, and this gradually increases in thickness. In 

 some cases the pellicle is distinct and complete, in others 

 it is absent. Under the microscope the comma bacilli in 

 the fluid and in the pellicle are seen to be connected into 

 beautiful spirilla, some of these measuring great lengths, 

 some as many as twenty to thirty turns, the long spirilla 

 more or less plicated and bent. 



The growth on Agar mixture is not characteristic, being 

 in the form of thin, translucent patches and films with 



