56 THE VITAMINES 



BACTERIA 



While yeast extract was used in 1904 by Bertrand (130) for the 

 growth of B. xylinum, it did not occur to anyone that this nutritive 

 medium possessed such special characteristics. Most bacteria, how- 

 ever, thrive well on the commonly used media. With some organisms 

 on the contrary, difficulties arise and consequently the method of 

 Noguchi (131), recommending the addition of a small amount of 

 testicular substance for the cultivation of spirochetes, denotes impor- 

 tant progress. What was responsible for the stimulating effect of 

 this tissue? The question remained unanswered till the war 

 came and the bacteriological laboratories were stripped of their 

 customary sources of supply of nutritive media. It became neces- 

 sary then, above all things, to replace Witte's peptone and nutrose. 

 Investigators found this difficult, till systematic work on this subject 

 was undertaken. On the whole, it may be said that most of the 

 nutritive media used before the war very likely owed their favorable 

 influence on the growth of bacteria to a small amount of vitamine 

 present therein. This conclusion was not apparent immediately, 

 since many investigators thought that bacteria could grow on a pure 

 synthetic medium. For instance, Vedder (132) cultivated the 

 meningococcus on starch prepared from cornmeal. Doryland (133) 

 reported success with pure synthetic media, which evidently con- 

 tained no vitamine. These experiments may be explained in that 

 the inoculation was perhaps so great, that, similar to yeast, growth 

 cook place. Pieper, Humphrey and Acree (134) reported great 

 success with synthetic media, while Lockeman (135) considered that 

 the factors necessary for the growth of the tubercle bacillus were 

 asparagine, as a source of nitrogen, glycerol and inorganic salts, 

 phosphorus, potassium and magnesium. Nevertheless, for other 

 microorganisms, other requirements appeared to be necessary, and 

 Bainbridge (136) believed that certain microorganisms could not 

 grow with protein as the only source of nitrogen. This view was 

 also maintained by Sperry and Rettger (137). Robinson and 

 Rettger (138) compared, in this connection, a protein obtained by 

 ferment action (which he called "Opsin"), with the products of 

 protein acid hydrolysis. Decolorization of the opsin by animal 

 charcoal decreased the value of that nutritive medium. Of the 

 proteins tested, the products of casein acid hydrolysis gave the best 

 results, but not so good as opsin. Extracts of beef worked very well. 



