116 INFECTIONS OF THE DIGESTIVE TRACT 



is very convenient to make use of the simple method, 

 recently described by Hans Zinsser 1 from the Depart- 

 ment of Pathology in Columbia University. Here two 

 crystallizing dishes are made to do service for obtaining 

 anaerobic growths . The smaller dish containing the inoc- 

 ulated agar is inverted inside the larger dish, the oxygen 

 being exhausted by the pyrogallic method. Water, on 

 the surface of which oil is placed, serves as a seal. This 

 method should serve to remove some of the obstacles to 

 the study of anaerobes. 



The identification of the anaerobes calls for a good deal 

 of patience and care. The anaerobic life of the large 

 intestine (especially in disease) having been so little 

 studied, it is not unlikely that new varieties will be found 

 which have heretofore escaped notice. A growth of 

 B. bifidus and other acidophiles occurs under anaerobic 

 conditions in both glucose and plain agar, if one takes 

 the precaution to make up the media so that they con- 

 tain 0.5 per cent, of acetic acid. 2 In the study of B. 

 aerogenes capsulatus it is important to use blood agar in 

 order to obtain the conditions proper for the growth 

 of these bacilli. The use of one cubic centimeter of 

 defibrinated rabbit's blood to eight cubic centimeters of 

 sugar agar answers well. 



In studying the characters of the organisms for the 

 purpose of identification the fermentation tubes are ex- 

 tremely helpful, as first pointed out by Professor Theo- 



1 " A Simple Method for the Plating of Anaerobic Organisms," 

 Journ. of Exper. Med., viii, p. 542, 1906. 



2 A beer-wort medium may be conveniently used. 



