70 LABORATORY BACTERIOLOGY 



cultures we could readily tell the one from the other. To 

 identify species, therefore, one must compare the cultural 

 characters of the organism in question with the description of 

 the species already known. As new media are constantly being 

 introduced, one often finds that the descriptions given in text- 

 books and manuals of bacteriology are very brief and, as com- 

 pared with modern requirements, insufficient to identify the 

 species. This has resulted in the listing of a very large num- 

 ber of species that are very difficult if not impossible to iden- 

 tify. With pathogenic bacteria the somewhat specific action 

 on experimental animals affords much aid in their identifica- 

 tion. For further explanations, see text-books. Matzuschita's 

 Baderiologische Diagnostik is especially helpful in diagnosing 

 species. 



