384 J. RUSSELL ESTY 



4. Longevity. The longevity of the vegetative forms has 

 already been discussed. If sugar media are used with meat extract 

 as the base, the life of the vegetative organism is about three 

 days; whereas if liver is used instead of meat extract the organism 

 survives from three to five days. In milk, the organism dies 

 out as a rule in from seventy-two to ninety-six hours. In lactose- 

 liver broth the cultures are in the vegetative stage after nine 

 days incubation. Starch and dextrin-liver-broth preserve the 

 life of the organism for four to six days in some cases, but does 

 not cause sporulation, whereas starch and dextrin broth made 

 from meat extract causes the death of the organism in three 

 to four days. Cultures in sugar media in the incubator die 

 out more rapidly than at room temperature. 



Cultures which contain spores may be preserved for many 

 weeks, and in some cases for over a year, provided anaerobic 

 conditions are maintained. The numbers of Clostridium Welchii 

 present in any culture and the longevity of the organism is 

 inversely proportional to the length of time necessary for the 

 appearance of "stormy fermentation." A covering of oil pro- 

 longs the life of this organism appreciably. 



VII. CULTURAL CHARACTERS 



1. Agar. a. Gas formation. Gas bubbles appear to some 

 extent in plain agar stab cultures, yet much more abundantly 

 and rapidly in agar containing sugar. In plain agar the presence 

 of gas is delayed from two to ten days, while in sugar agar, 

 fermentation takes place very quickly. Bubbles appear at first 

 along the line of growth, but ultimately permeate the entire 

 medium. At 35° to 37° gas production is most abundant. 



On plates of glucose agar, numerous gas bubbles are present 

 after 15 hours growth if the plates are heavily seeded with the 

 organism. From the spaces occupied by the bubbles, as well 

 as upon the surface of the agar, a turbid fluid is pressed out, 

 due to the bacteria present. Deep stab cultures in tubes of 

 glucose agar are accompanied by abundant gas production which 

 results in the fragmentation of the medium and the extrusion 

 of turbid fluid on the surface. 



