1694 Journal of Applied Microscopy 



A Review of the Existing Methods for Cultivating Anaerobic 



Bacteria. 



Since the discovery by Pasteur in 1861 of the fact that some species of bac- 

 teria can thrive in the absence of oxygen only, various methods have been intro- 

 duced involving many devices for the study of anaerobic bacteria. Notwith- 

 standing this fact, our knowledge of anaerobes is as yet very limited. While 

 bacteriology has made rapid progress along the line of aerobic species, a compar- 

 atively small number of anaerobic species have been carefully studied and 

 identified. 



Concerning the character of some of the known anaerobes, such as the bacilli 

 of tetanus, of malignant cedema, and of black leg, it becomes evident that the cause 

 of the slow development in the study of anaerobic species does not lie in the fact 

 that these species are of less pathologic and economic importance than their 

 brothers the aerobes. Nor can it be attributed to the assumption that this class 

 of organisms covers a very limited number of species only, for the results of 

 bacteriological research of recent years are rapidly revealing the existence of a 

 liberal distribution of anaerobic bacteria in nature. 



On the other hand, the bacteriologist realizes that the production of anaerobic 

 conditions for bacterial growth involves greater difficulties and meets more fre- 

 quently with failure than the simple cultivation of aerobes. It is, therefore, 

 reasonable to recognize this greater difficulty, complexity and expense of technique 

 as the most potent obstacle in anaerobic research. 



While, from the above statement, it is obvious that none of the methods for 

 anaerobic cultures are quite so simple and easy as those for aerobes, still, a 

 thorough review of the multitude of methods introduced and devices invented 

 shows that there are some that involve little difficulty, are simple, and can be 

 manipulated in any laboratory. Methods for the cultivation of anaerobic bacteria 

 are referred to in most text-books and manuals on bacteriology ; however, space 

 in such books does not permit a full list of these methods, with directions for 

 practical application ; and a search through the entire bacteriological literature 

 in pursuit of the easiest, simplest and most efficient method is a task that does 

 not appeal to the investigator eager to grow cultures with the greatest economy 

 of time. In order to fill this gap, to afford the investigator easy access to the 

 existing methods, and by so doing encouraging the study of anaerobic 

 bacteria, it was thought desirable to carefully review the literature on this 

 subject, and to present the principal methods and their modifications in this 

 article. 



For the purpose of being able to treat the diverse methods in logical order, 

 the principles upon which they are based are arranged in the following classifi- 

 cation, in which order they will be reviewed. 



The Anaerobic conditions are brought about : 



1. By formation of a vacuum. 



2. By replacement of air by inert gases. 



