Other Intestinal Bacteria. i6l 



of organisms, the anaerobic spore-forming bacilli,' of which 

 the B. sporogenes is a type. This form was isolatpd by 

 Klein (Klein, 1898; Klein, 1899) in 1895, in the course 

 of an epidemic of diarrhoea at St. Bartholomew's Hos- 

 pital, and described under the name of B. enteritidis 

 sporogenes; it is closely related to the B. aerogenes capsu- 

 latus of Welch (Welch and Nuttall, 1892). 



Klein's procedure for isolating the B. sporogenes is 

 simple in the case of highly polluted waters. A portion 

 of the sample to be examined is added to a tube of sterile 

 milk, which is then .heated to 80° C. for ten minutes 

 to destroy vegetative cells. The milk is next cooled and 

 incubated under anaerobic conditions, which may be 

 accomplished most conveniently by Wright's method. A 

 tight plug of cotton is forced a quarter way down the test 

 tube, the space above is loosely filled with pyrogallic acid, 

 a few drops of a strong solution of caustic potash are 

 added, and the tube is tightly closed with a rubber stopper. 

 After eighteen to thirty-six hours at 37 degrees the appear- 

 ance of the tube will be characteristic if the B. sporogenes 

 is present. "The cream is torn or altogether dissociated 

 by the development of gas^ so that the surface of the 

 , medium is covered with stringy, pinkish-white masses of 

 coagulated casein, enclosing a number of gas-bubbles. 

 The main portion of the tube formerly occupied by the 

 milk now contains a colorless, thin, watery whey, with a 

 few casein lumps adhering here and there to the sides of 

 the tube. When the tube is opened, the whey has a smell 



