BACTERIOLOGICAL TECHNIQUE. 233 



made a gas-pressure regulator is added to the thermo- 

 regulator. Incubators are also both warmed and regu- 

 lated by electricity. 



In emergencies a culture may be developed at the 

 blood temperature by placing it in water contained in 

 a small vessel, which itself is contained in a larger 

 vessel, also filled. By adding a little hot water from 

 time to time the temperature can readily be kept be- 

 tween 34 and 38 C., which is sufficiently uniform for 

 bacteria such as the diphtheria bacilli to grow. 



As a temporary expedient during the night, when 

 haste is necessary, it is possible, when the culture medium 

 is solid and within a strong glass tube or metal case, 

 to make use of the body heat by putting it under the 

 clothing next to the body and sleeping upon it. Natu- 

 rally, this should only be done when other means fail. 

 Several times, when in the country, this method has 

 enabled the writer to obtain a growth of diphtheria 

 bacilli over night, and thus get important information, 

 when otherwise it would have been impossible. 



Culture Methods for Anaerobic Bacteria. 



Anaerobic bacteria will scarcely be cultivated except 

 in bacteriological laboratories, where the technique is 

 already understood, so that the methods employed in 

 their culture will only be touched on here. A simple 

 device is that of Koch, who placed a thin strip of 

 sterile mica upon the still fluid agar or gelatin in the 

 Petri dish, which had already been inoculated. After 

 the solidification of the media the portion under the 

 mica is excluded from the air and anaerobic growth can 

 develop. A second simple method (Liborius) is to fill 

 the tubes with media fuller than usual and to inoculate 



