INFECTIONS OF THE DIGESTIVE TRACT 131 



the anaerobe just mentioned, and the two organisms 

 can be positively distinguished only by making blood- 

 agar cultures under aerobic and anaerobic conditions. 

 The growth of the organisms is usually slighter in a 

 sugar-free tube than in the ones containing sugar. The 

 diplococcal forms, especially, are apt to grow poorly 

 in the peptone bouillon and may quite fail to multiply. 

 In material containing large numbers of the plain form 

 of B. bifidus one finds in the sugar tubes large numbers 

 of this organism in its bifid form. Very beautiful 

 branching forms, presenting considerable variety in 

 their morphology, may be observed. One has this ex- 

 perience especially with the lactose and dextrose bou- 

 illon, and I think the growths of Hfidus are apt to be 

 especially luxuriant in the lactose-bouillon tube. The 

 so-called punctate form already described is very com- 

 mon in the fermentation tubes. 



Under pathological conditions one may meet with 

 different bacterial elements in the sediments. In cases 

 in which the intestine contains large numbers of positive 

 diplococci or streptococci, there is an abundant growth 

 of positive diplococcus forms and streptococcus forms in 

 the sugar tubes. One may find streptococcus forms very 

 abundant even hi cases where the tubes have been inocu- 

 lated from flora not containing a strikingly increased 

 number of such bacteria. As a rule a .very great pre- 

 ponderance of streptococcal and diplococcal forms in the 

 fermentation tubes points to an excess of such organisms 

 in the digestive tract. By the use of this method atten- 

 tion has sometimes been drawn to this -type of bacterial 



