110 



ESSENTIALS OF BACTERIOLOGY. 



Stab Culture. After 30 hours a growth can be distinguished 

 along the needle track, and on the surface a little cavity has 

 been formed, filled up by a bubble of air, and this liquefaction 

 proceeds until on the sixth day it has reached the sides of the 

 tube, tapering, funnel-shaped to the bottom of the tube. After 



several weeks the spirilla 



F IG ' 58. are found in little collec- 



tions at the bottom of the 

 fluid gelatine. In eight 

 weeks the bacilli have 

 perished. 



Agar. Stroke cultures. 

 A shiny white layer lasts 

 many months. 



Potato. A yellow honey- 

 like transparent layer, if 

 the potato is kept at ani' 

 mal heat. 



Bouillon. A wrinkled 

 scum is soon formed in 

 bouillon. They live well 

 and grow in sterilized milk 

 and sterilized water, re- 

 maining virulent in the 

 latter for many months. 



In ordinary water, the bacteria present are destructive to the 

 comma bacillus, and they die in a few days. 



Staining. They are colored well with watery aniline solu- 

 tions. The flagella can be well seen by staining according to the 

 flagella stain. 



Pathogenesis. Experiment animals are not subject to cholera 

 Asiatica, but by overcoming two obstacles Koch has produced 

 choleraic symptoms in guinea-pigs. Nicati and Rietsch pre- 

 vented peristalsis and avoided the acidity of the stomach juices 

 by direct injection into the duodenum, after tying the gall-duct. 

 Koch alkalinizes the gastric juice with 5 c.cm. of 5 per cent, 

 sol. of sodii carbonas, and then injecting 2 grams of opium tinc- 

 ture for every 300 grams of weight into the peritoneal cavity 



Cholera colonies after 30 hours 100 X. (Friinkel 

 and 1'feiffer.) 



