362 IMPORTANT VARIETIES OF FISSION-FUNGI 



rarely in the heart's blood. The more virulent the 

 organisms, the more they spread into the organs. 



(d) In animals : Spontaneous cholera in animals caused 

 by cholera vibrios is unknown. (Compare Vibrio Met- 

 schnikovii, p. 366.) Our domestic animals, etc., appear 

 to be immune to cholera infection, as it occurs in natural 

 ways. (See below.) 



Experimental Observations Regarding Pathogenic 

 Effects. — (a) In animals: According to Sabolotny (C. B. 

 xv, 150), the Spermophilus guttatus, a rodent of southern 

 Russia, dies after being fed cholera vibrios with symptoms 

 and section findings resembling those of cholera. Positive 

 results per os were also obtained by Metschnikoff in young 

 rabbits, by Wiener in sucking kittens and young (five 

 days' old) rabbits, and by Karlinski in young dogs. (See 

 Wiener, C. B. xix, 205, 595. ) In adult guinea-pigs by the 

 natural channels, only an approximation to the picture of 

 a case of cholera can be produced. Usually, following 

 Koch's method, 5 c.c. of a 5% solution of soda is first 

 introduced into the stomach, and shortly afterward 10 c.c. 

 of a cholera culture in bouillon; at the same time 1 c.c. 

 of tincture of opium to each 200 gm. of body-weight is 

 injected intraperitoneally to quiet the intestinal peristalsis. 

 Death occurs in twenty-four to forty-eight hours, preceded 

 by a falling of temperature and extreme prostration. The 

 intestine is reddened and contains abundant fluid, rich in 

 cholera vibrios. Other vibrios, Vibrio proteus, etc., pro- 

 duce similar but not so pronounced effects. It is easier 

 to kill animals (rabbits, guinea-pigs) by the introduction 

 of the organisms into the blood-vessels or serous cavities. 

 Death in peritoneal infection occurs in twelve to sixteen 

 hours, usually after a primary multiplication, from the 

 action of absorbed toxins originating from the dead 

 vibrios (R. PfeifTer). In the peritoneum (and eventually 

 in the blood and organs) of the dead animal, living vibri- 

 ones are usually found only when the infection has been 

 produced with very large quantities. Many other bacteria 

 operate exactly the same. (See p. 360 regarding the poi- 

 sons of cholera. ) If an animal withstands a single intra- 

 peritoneal infection with a small dose of living vibriones, 

 it becomes immune to larger doses, because the bacterici- 



