XVI 



VIBRIO AND SPIRILLUM 



427 



pig ; the animals died in thirty to forty hours, the blood 

 and the intestine, Hver, and spleen containing numerous 

 vibrios. Now, when testing the cultures of cholera vibrios 

 derived from different cases of undoubted cholera asiatica 

 and grown on the slanting surface of solidified nutrient 

 Agar for a day or two it will be found that they possess 

 different degrees of virulence. Of some varieties ^ or ^ of a 

 culture produces distinct tumour at the seat of inoculation and 



Fig. 



174. 



Fig. 



175- 



From an Artificial Cultivation of chole- 

 raic Comma-bacilli in Gelatine 

 Peptone. Magnifying power 700. 

 Most of these are single curved 

 bacteria, a few are joined end to 

 end in twos, thus forming S-shaped 

 organisms ; and a few are in chains 

 of several placed end to end. 



From an Artificial Cultivation of chole- 

 raic Comma-bacilli in Agar- Agar 

 Peptone at the ordinary tempera- 

 ture of the room after several 

 weeks. The Comma-bacilli change 

 by vacuolation into plano-convex, 

 then biconvex organisms. Magni- 

 fying power about 700. 



death in thirty to forty-eight hours with all the appearances 

 of general septicsemic infection, while with other varieties 

 double and treble this dose produces only a transitory 

 tumour with transitory constitutional disturbance ; after 

 several days the animals completely recover, or at most 

 ulceration of the skin about the seat of the tumour and 

 ultimate recovery takes place. R. Pfeiffer and Metschnikoff 

 have had cultures of cholera vibrios which in small doses 

 produced general septicsemic infection of the guinea-pig 

 after subcutaneous injection. The greater or lesser virulence 

 of the cholera vibrios (tested by subcutaneous injection of 



