1 66 BACTERIA. 



These two animals died, and the contents of their small 

 intestine were used in the same way, and so on through ten 

 generations. Of twenty-one animals thus treated, two 

 recovered, nineteen died. The doses varied from 0.5 to 

 2.5 c.c. 



It is sometimes argued that in consequence of the difference of the 

 symptoms in animals (especially guinea pigs), and in man, under these 

 conditions of infection by the stomach, the disease cannot be the same, and 

 it is pointed out that vomiting and profuse diarrhoea are entirely absent in 

 cholera, experimentally produced. Against this objection may be put the 

 fact that there is usually in the guinea pig a large accumulation of fluid 

 transudation in the small intestine and even in the stomach ; whilst in the 

 very acute forms of cholera the pathological appearances presented in the 

 intestines are almost identical with those found in man. In exceedingly 

 acute cases the peritoneum presents a dark colour and a peculiar glistening 

 mucous appearance, which is very characteristic, and seems to be associated 

 with the tarry condition of the blood. The mucous surface of the intestine 

 is usually congested, and in the intestinal canal is a considerable quantity 

 of serous fluid, in which are floating the small white rice-like bodies which are 

 merely portions of desquamated epithelium and mucus. There is usually, at 

 this stage, marked injection of the vessels of the solitary glands, and at 

 the periphery of the Peyers patches, and the longer the patient remains alive 

 the more accentuated become these appearances. It is only in the later 

 stages of the disease, or during the period of reaction, that the swelling 

 of the follicles is very marked, and that more or less extensive ulceration 

 of the mucous membrane may be observed. The dejecta, of course, are 

 similar in character to the contents of the bowel, are watery owing to the 

 great amount of serous effusion, and contain the rice-like bodies in which 

 are found the comma bacilli. Bacilli are also found lying free in the 

 watery fluid. The dejecta have little or no odour, and when they are 

 allowed to stand they separate into two layers an upper slightly grumous 

 layer, and a lower grey deposit. "Neutral, or slightly alkaline, they con- 

 tain a very small proportion of organic or inorganic salts one to two per 

 cent. which consists of chloride of calcium, carbonate of ammonia, potash, 

 salts, and a small quantity of urea. They contain little or no albumen, and 

 during the first day or two no bile pigments." 



If microscopic sections of the lower part of the small 

 intestine be made, and stained according to LofHer's 

 method, 1 the bacilli may be seen with the aid of a high 



1 First stain in a solution of Leonhardi's Dresden methyl violet ink, and 

 then in an alkaline solution of fuchsin, which is made up as follows : 

 100 c.c. aniline water. 



1 c.c. of a solution of one per cent, of caustic soda. 



2 grammes of solid fuchsin. 



The whole is well shaken, after which the specimens may be left in it for 

 twenty-four hours ; the sections are then washed in distilled water acidu- 

 lated with a drop of acetic acid, dehydrated in absolute alcohol, cleared up 

 in cedar oil, and mounted in Xylol balsam. 



