CHAPTER VII. 
PATHOGENIC ANAEROBES. 
Anaerobic bacteria may be furnished conditions, which permit of their development, 
in a variety of ways and a very considerable number of pieces of apparatus have been 
devised to secure this end. In a general way all of the methods may be grouped under 
the following heads: 
1. Displacement of air. 
2. Absorption of oxygen. 
3. Exhaustion of air. 
4. Exclusion of air. 
5. Miscellaneous methods, in the presence of reducing substances as litmus, or 
a strongly aerobic germ, etc. 
The first two methods are the most reliable. In the displacement method, hydro-' 
gen, carbon dioxide or illuminating gas may be used; hydrogen is best. This gas is 
readily prepared by the action of sulphuric acid (1:8) on zine. Either a Kipp generator 
may be used or one of a simpler construction. The gas should be washed, 1st. in lead 
nitrate to absorb the sulphuretted hydrogen, 2nd. in silver sulphate to absorb any 
arseniuretted or phosphuretted hydrogen, and 8rd. in potassium hydrate to remove sul- 
phur and carbon dioxide. 
The cultures are made in media containing glucose (which should preferably be 
freshly prepared and always boiled immediately before being inoculated), either as test- 
tube or plate cultures. Novy’s anaerobic jars are perhaps the most satisfactory recep- 
tacles for the cultures. (For careful description of same, see N. 306.) 
In the second method (Buchner’s method) an alkaline solution of pyrogallic acid 
_ is used to absorb the oxygen. The cultures may be placed in Novy jars or similar re- 
ceptacles; for tube cultures a large wide mouthed bottle fitted with a rubber cork does very 
well. The dry pyrogallic acid is placed in the bottom of the receptacles, about 1 gram 
to every 100 ce. of air space, the tubes are put in place, then about 10 ce. of a 
normal sodium hydroxide is added to each gram of pyrogallic acid, and the apparatus 
immediately and hemetically sealed. 
REFERENCES. A. 206; L. & K. 98; M. & R. 68; M. & W. 117; McF. 153; P. 
233; S. 78. 
