GROWTH OF BACTERIA IN PROTEIN-FREE PRODUCTS 227 



Liebig's meat extract (0.5 per cent) considerably improved the 

 medimii. The color of B. prodigiosus cultures was not nearly as 

 brilliant as on the edestin product alone, but the fluorescent pig- 

 ment was formed by B.fluorescens and B. pyocyaneus. 



It was found that the growths on the lactalbumin product 

 paste were much better on 2 per cent of the paste than on 4 per 

 cent, and slightly better than on 1 per cent. Too large an amount 

 of this strongly acid paste on neutralization probably formed 

 enough NaCl to be inhibitory. In general, this product was a 

 better culture medium than the edestin, but inferior to the 

 casein product. 



THE GROWTH OF ANAEROBES IN THE PROTEIN-FREE DIGESTION 



PRODUCTS 



It was surprising to find that not only B. teta7ii, B. aerogenes 

 (capsulatus) and B. botulinus, but also the putrefactive organisms, 

 B. edematis (maligni), B. anthracis-symptomatici and^. putrificiis, 

 grew well on the different protein-free digestion products, especi- 

 ally opsine. 



In 2 per cent opsine B. edematis (maligni) and B. anthracis- 

 symptornatici gave very heavy growths in from twenty-four to 

 thirty-six hours. After three days of incubation spores became 

 abundant and only a few bacilli remained. Repeated trans- 

 plantation in this medium did not apparently affect the viability 

 of these organisms. 



In 2 per cent opsine plus 1 per cent glucose the growths were 

 even more luxuriant, but the morphology of the bacilli was not the 

 same as it was in the plain opsine. The bacilli were longer and 

 thinner. Many were granular and stained poorly. Spore 

 formation was indefinitely delayed, and the organisms underwent 

 marked granulation and degeneration. 



B. aerogenes [capsidaius) grew fairly well in 2 per cent opsine 

 during three days' incubation. No spores were formed in plain 

 or glucose-containing opsine. B. putrificiis yielded a good growth 

 in plain and in glucose opsine in five days. B. botulinus underwent 

 rapid development in two to three days. 'Spore formation was 



