60 THE VITAMINES 



Tubercle bacilli were cultivated by Sazerac (153a) and by Masucci 

 (153b) on digested casein (aminoids). 



In regard to hemophilic bacteria, there is the work of Davis (154). 

 For this type, two factors in particular are of great importance. One 

 is hemoglobin, and the other is a substance which is found in other 

 strange bacteria, as well as in a variety of fresh plant and animal 

 tissues. This second substance is found in B. influenza when both 

 strains are cultivated together. The similarity of the factors neces- 

 sary for the growth of rats with those necessary for the successful 

 growth of hemophilic bacteria has been emphasized by Davis. He 

 explained it by the fact that hemoglobin serves as the source of iron, 

 while the second substance facilitates the assimilation of this element. 

 In a later publication, Davis (155) found that the growth-promoting 

 influence of hemoglobin, white and brown rice, pure wheat flour and 

 wheat bran, was shown by no other kinds of bacteria except by the 

 hemophylic. Germinated rice or wheat kernels exhibit a greater 

 influence than ungerminated. In this case also, the active substance 

 was adsorbable by filter paper and was quite thermo-stable, having 

 resisted a temperature of 100C. for one to two hours. 



The favorable influence of cooked meat on bacterial growth was 

 observed by Wolf and Harris (156), on the B. histolyticus,andby 

 Wolf (157) on the vibrion septicus, B. sporogenes, B. welchii and B. 

 proteus (158). Boyer (159) recommended a hydrochloric acid extract 

 of finely divided bones for the cultivation of streptococci, and Otabe 

 (160) suggested a wheat extract instead of meat for staphylococci. 

 We can see from this short list that the addition to the medium of a 

 natural product as a source of vitamine was necessary. For the 

 cultivation of B. coli, Dienert and Guillerd (161) prepared a medium 

 as follows: 500 grams of pressed yeast were heated to 50C., the 

 optimum temperature for the action of endotryptase. In less than 

 24 hours the autolysis was finished, the yeast having become liquid, 

 yielding 397 cc. of filtrate which was then diluted to two liters. The 

 extract was sterilized for a half hour at 100C., and finally diluted to 

 7500 cc. This preparation was used advantageously instead of 

 peptone. 



Bunker (162) and particularly L. David and Ferry (163) have 

 made an exact study of the conditions that are necessary in order to 

 obtain a very active toxin from cultures fo B. diphtheriae. It was 



