208 BACTERIOLOGY. 



duciug-ageut. They recommend formic acid or sodium 

 formate in 0.3 to 0.5 per cent. ; glucose in 1.5 to 2 per 

 cent. ; or blue litmus tincture in 5 per cent, by volume. 

 This is, of course, in addition to an atmosphere from 

 which all oxygen has been expelled. As a reducing- 

 agent for this purpose, Theobald Smith regards a weaker 

 solution of glucose, 0.3 to 0.5 per cent,, as more ad- 

 vantageous; and Wright obtains better results when 

 glucose is added if the primary reaction of the media 

 is about neutral to phenolphtalein. 



Method of Park. A very simple, convenient, and 

 efficient method is employed by Park. It consists in 

 covering the medium in which the anaerobic species are 

 to be cultivated with liquid paraffin (albolene). The 

 best results are obtained when the amount of* paraffin 

 added is about half that of the liquid in the tube or 

 flask. The liquid paraffin has the advantage over the 

 solid paraffin in not retracting from the walls of the 

 vessel on cooling. All air is expelled from flasks or 

 tubes prepared in this way, by heating them in the auto- 

 clave. The layer of paraffin prevents the reabsorption 

 of oxygen driven off by the heat. After cooling, the 

 inoculation is made by passing the needle through the 

 paraffin well down into the media. 



Many other methods are employed for this special 

 purpose, but for the beginner those given will suffice. 



From what has been said, it may be inferred that the 

 cultivation of anaerobic bacteria is a simple matter 

 attended with but little difficulty. Such an opinion 

 will, however, be quickly abandoned when the beginner 

 attempts this part of his work for the first time, and 

 particularly when his efforts are directed toward the 



