390 TYPHOID FEVEE 



the degree seems to be in inverse ratio to the amount of gas formation. 

 Very typical is the growth in milk, and it is by this medium that 

 isolation can be best effected. A small quantity of the material 

 suspected to contain the bacillus is placed in 15 to 20 c.c. of sterile 

 milk, which is then heated for ten minutes at 80 C. to destroy all 

 vegetative bacteria ; the tube is cooled, placed under anaerobic con- 

 ditions, and incubated at 37 C. for from twenty-four to thirty-six hours. 

 If the bacillus be present there is abundant gas formation, and almost 

 complete separation of the curd from the whey takes place. The former 

 adheres to the sides of the tube in shreds, and large masses gather with 

 the cream on the top of the fluid, all being torn by the gas evolved. The 

 whey is only slightly turbid, and contains numerous bacilli. The growth 

 lias an odour of butyric acid. If a small quantity (say 1 c.c.) of 

 the whey be injected into a guinea-pig, the animal becomes ill in a few 

 hours and dies in twenty-four hours. At the point of inoculation, the 

 skin and subcutaneous tissues, and sometimes even the subjacent muscles, 

 are green and gangrenous and evil-smelling, there is considerable oedema, 

 and there may also be gas formation. The exudation is crowded with 

 bacilli, which, however, are not generally distributed in any numbers 

 throughout the body. These pathogenic properties of the bacillus 

 enteritidis sporogenes are important in its recognition, for its culture 

 reactions taken alone are very similar to those of the bacillus butyricus of 

 Botkin. 



SUMMER DIARRHOEA. 



As has been already stated, the bacillus of dysentery, the 

 b. coli, and the b. enteritidis sporogenes have been found 

 associated with epidemics of this disease. This indicates that 

 the condition may be originated by a variety of organisms, and 

 it is further probable that the clinical features in different 

 epidemics vary. This is to a certain extent illustrated by the 

 condition of the stools. In Britain these are usually green, 

 watery, slimy, and putrid, without blood or mucus, but in many 

 outbreaks in America blood and mucus are present. The 

 multiple origin of the disease has been illustrated by the work of 

 Morgan, who, in a careful investigation of the disease in Britain, 

 has been unable to find evidence of the dysentery bacillus being 

 present. He has, however, very frequently (in 63 per cent. 

 of the cases examined) found in the stools and intestine a 

 bacillus (" Morgan's No. 1 bacillus ") which is a motile Gram- 

 negative organism producing acid and slight gas formation in 

 glucose, laevulose, and galactose, and no change in mannite, 

 dulcite, maltose, dextrin, cane-sugar, lactose, inulin, amygdalin, 

 salicin, arabinose, raffinose, sorbite, or erythrite ; it further 

 causes indol formation, and in litmus milk slowly originates an 

 alkaline reaction. It produces diarrhoea and death in young 

 rabbits, rats, and monkeys when these animals are fed on 

 cultures. It is thus possible that in this bacillus we have 



