194 CLINICAL BACTERIOLOGY. 



(&) Peptone -culture (Fertilizing Method, Schottelius, 

 Kocli). The plate-method, which yields admirable results 

 in the diagnosis of marked cases of Asiatic cholera, does 

 not suffice, however, for other cases in which the dejections 

 contain only a small number of comma-bacilli. This small 

 number of vibrios are overrun on plates by the fecal bac- 

 teria, and do not develop at all. It is, therefore, necessary 

 in every suspected case to adopt, in addition to the original 

 plate- method, a further method of investigation : namely, 

 the preparation of peptone-cultures. It has previously 

 been pointed out (p. 184) that the cholera-vibrios thrive 

 especially well in a simple alkaline solution of peptone 

 and sodium chlorid (one per cent, peptone and one-half 

 per cent, sodium chlorid). It may be added that the 

 vibrios, by reason of their motility and their great need of 

 oxygen, tend toward the surface of the liquid culture- 

 medium, and there undergo enormous multiplication. 

 Upon both of these facts is based the method of peptone- 

 culture, which has the further great advantage that it leads 

 to the desired result much more rapidly than the plate- 

 method. A platinum loopful of the suspected feces, or, if 

 this be obtainable, a flake of mucus, is introduced into a 

 test-tube or an Erlenmeyer flask containing the solution 

 described, and the vessel is exposed in the thermostat to a 

 temperature of 37 C. (98.6 F.). As soon as the fluid 

 exhibits the slightest traces of turbidity, which usually 

 occurs in the course of from six to ten or twelve hours, a 

 specimen is taken from the surface and is examined in 

 hanging drop and in dry cover-slip preparations. If the 

 examination discloses the presence of a pure culture of 

 cholera-vibrios, the diagnosis is almost certain. In most 

 cases, however, the procedure is not quite so simple. In 

 the superficial layer of the peptone-solution the vibrios are 

 usually intermixed with other microorganisms, and most 

 frequently with the bacterium coli commune. There then 

 remains nothing but to make plates from the material on 

 the surface. These plates, however, are made under much 

 more favorable conditions. 



There is now no longer any danger that the small 

 number of cholera-bacilli that were present originally in 

 the feces will be overrun in their growth. Through the 

 intermediation of the peptone-culture the vibrios have 

 undergone enormous multiplication, and the Petri dishes 



