380 J. RUSSELL ESTY 



In market milk spores of Clostridium Welchii may enter as a 

 contamination, but do not germinate except under very special 

 conditions. Spores germinate rapidly in sterilized milk and 

 remain in the vegetative stage without again forming spores. 

 Clostridium Welchii has never been found to occur in nature 

 in the vegetative form. This is undoubtedly due to its strictly 

 anaerobic requirement and its inability to withstand an unfavor- 

 able environment. Clostridium Welchii never sporulates in the 

 tissues, organs and body fluids of the living animals but does 

 sporulate in the intestine. 



Spores of Clostridium Welchii do not develop below 10°, and 

 die out slowly at this temperature. Market milk, when heated 

 to 80° to 85° for fifteen minutes and then kept on ice, shows no 

 evidence of decomposition or fermentation due to Clostridium 

 Welchii, but when allowed to stand above 20°, the characteristic 

 "stormy fermentation" occurs in from twenty-four to seventy 

 four hours. If the milk has not been heated to 80° to 85° for 

 fifteen minutes, Bacterium coXi and the other facultative aerobes 

 multiply in excess of Clostridium Welchii and thus obscure its 

 action, producing a peculiar non-characteristic digestion and 

 decomposition of the milk. 



2. Morphology of spores. Great irregularity is observed in 

 the size, shape and location of the spores. They are usually 

 oval, from 1.5 micra to 3 micra long and slightly thicker than 

 the diameter of the bacillus. The spores form in the middle of 

 the rod or slightly toward one end. They present, in preparations 

 stained by Hauser's method, an unstained glistening appearance 

 of a highly refractive character, while the ends of the organism 

 stain deeply and completely. 



8. Germination of spores. On germination, the spores show 

 •first a change in their refractive property; this is followed by 

 elongation, with a final bursting through of the spore membrane 

 at one pole and the outgrowth of the bacillus. Germination 

 takes place in media containing glucose, galactose, lactose, 

 maltose, sucrose, dextrin and starch. If there is a sufficient 

 amount of the fermentable substance present, all the spores 

 germinate. After all fermentable material is exhausted any 



