490 THE CHOLERA VIBRIO 



Animals. 



I. Animals suffer no harm from being fed with cultures of the vibrio or 

 with cholera stools ; Nicati and Rietsch therefore, with the object of inocu- 

 lating the material directly into the intestine, injected cultures into the 

 duodenum of guinea-pigs after laparotomy. These observers were the first 

 to produce intestinal cholera experimentally. 



II. Koch obtained the same results but in another way. He injected 

 directly into the stomach of a guinea-pig through an cesophageal tube, first 

 a few c.c. of a 2 per cent, solution of carbonate of soda and a few minutes 

 later a culture of the vibrio : at the same time tincture of opium (1-1 '5 c.c.) 

 was inoculated either into the peritoneal cavity or beneath the skin (Doyen 

 uses 40 per cent, alcohol instead of opium). The animal died in two or three 

 days from diarrhoea and collapse. Post mortem, the small intestine contained 

 a watery fluid in which cream-coloured flakes were suspended and which 

 yielded an almost pure culture of the vibrio. 



III. Zattolotny showed that ground squirrels are very susceptible to infec- 

 tion with the cholera vibrio : if a number of these animals be fed with 

 foodstuffs watered with a few drops of a pure culture of the vibrio, half the 

 number become infected and die ; the mortality is heavier if an alkaline 

 salt be added to the infected meal, though some of the animals even then resist 

 infection. The affected animals become weak and frequently suffer from 

 diarrhoea, sometimes also from cramp with cyanosis of the nose and tongue ; 

 the temperature is sub-normal. Post mortem the intestinal canal is dis- 

 tended and hyperaemic and contains a fluid rich in vibrios ; the latter often 

 gain access to the peritoneal cavity and blood stream. 



IV. Metchnikoff, conceiving the immunity of animals to intestinal cholera 

 to be largely due to the action of organisms normally present in the intestine, 

 experimented with a view to overcoming or at least diminishing such pro- 

 phylactic action if it existed. He fed a number of young rabbits solely 

 on their mothers' milk for some weeks : the intestinal flora under these 

 conditions remained for a long time quite poor and but little varied. The 

 growth on a twenty-four-hour agar culture (Massaouah vibrio *) was scraped 

 off with the bent end of a pipette and placed in the mouth of the young 

 rabbits : in about one-half the cases the animals suffered from diarrhoea 

 -and died of intestinal cholera about the sixth day. Post mortem the intes- 

 tines showed the characteristic lesions of cholera and numerous vibrios were 

 found in the contents of the intestine. 



V. Young chimpanzees can be fed with large quantities of the cholera 

 vibrio without showing any symptoms. 



VI. Ancillary micro-organisms. Metchnikoff, after showing that in gelatin 

 plate cultures some micro-organisms favour the growth of the cholera vibrio, 

 investigated these ancillary properties particularly with regard to three 

 organisms isolated from the human stomach, viz. : a white sarcina, a torula 

 and a bacillus belonging to the colon group. Twenty out of twenty-two 

 young rabbits fed with a mixture of the Massaouah vibrio and these organisms 

 died of cholera. As a rule death occurred 36-48 hours after infection, but 

 in a few cases was longer delayed ; nearly all the animals were dead within 60 

 hours. The infected animals suffered from a watery diarrhoea with a colour- 

 less, serous, alvine discharge containing lumps of mucus : vomiting was 

 rare, but suppression of urine very common. The abdominal walls were 



1 A vibrio isolated from some water at Versailles was found to be virulent for guinea- 

 pigs on intra-peritoneal inoculation and to have the same effect on young rabbits as the 

 Massaouah vibrio. 



