GENERAL CONSIDERATIONS 9 



37 C. Only glucose, lactose, raffinose and mannite were em- 

 ployed. Their percentages of positive results were as follows : 



Human Equine Bovine 



Glucose 89 84 65 



Lactose ... ... 62 8 52 



Raffinose ... 6 4 28 



Mannite ... ... 28 2 6 



Streptococci from sources other than excreta tested in the 

 same way do not show differences sufficiently distinctive to 

 enable the excretal origin of any streptococcus to be ascertained 

 from an examination of its biological properties. v 



For the examination of water, soil, etc. the differentiation of 

 the isolated streptococci has not up to the present proved to be 

 of any immediate practical value. 



A classification of streptococci on this basis has on the other 

 hand proved to be of value in differentiating certain human 

 streptococci and for the identification of streptococci in air. 

 The classification adopted is discussed in Chapter IX. 



B. enteritidis sporogenes. 



This bacillus was isolated in October, 1895, by Klein from 

 the intestinal discharges of patients at St Bartholomew's Hospital 

 suffering from an epidemic of diarrhoea. It was also isolated 

 from the milk supplied to these patients. 



It is a strictly anaerobic organism with fairly definite char- 

 acters, of which the most important are the following : A fairly 

 large bacillus r6 to 4-8 p long and about 0*8 //, thick. Motile, 

 and stains by Gram's method. It readily forms spores, which 

 are usually present near the ends of the rods. 



Under anaerobic conditions it grows well in milk, glucose 

 agar, and upon blood serum and other media. Milk cultures are 

 especially characteristic, and this medium is usually used for its 

 isolation. The milk is coagulated and separated into a stringy 

 material (coagulated casein) and a clear or somewhat turbid 

 whey, a scattered layer of cream remaining on the top, which is 

 broken up by the gas which is readily liberated by shaking the 

 tube. The whey is acid, and the tube-contents smell of butyric 

 acid. The whey examined microscopically shows the bacilli. 



