1023] 



CAMP — CITRIC ACID AS A SOURCE OF CARBON 



291 



In cultures of Phomopsis in the presence of large amounts of 

 citrates a marked yeasty smell suggesting ethyl alcohol and dilute 

 acetic acid developed after a prolonged growth period; with only 

 dextrose and peptone no such odor developed. Both of the 



Alternaria spp. in dextrose 



mixtures developed similar 



odors, and distillation gave solutions with the odor of alcohol. 

 These distillates gave iodoform tests on warming and benzoates 

 with the odor of ethyl benzoate, or suggesting mixtures of ethyl 

 benzoate with allied benzoates. When a series in which KNO, 

 was used as the source of nitrogen was inoculated with Oospora 

 Citri-aurantii the growth was so slow and the difficulties connected 

 with filtering off the organism so great that the series had to be 

 abandoned. After about 2 weeks a very marked sweetish odor 

 developed, nearly resembling slightly fermented cider, and this 

 applied in less degree to the culture solution where only dextrose 



used as the source of carb 



On distillation the odorous 



compound was carried over to the distillate and suggested 



of ethyl or some 



allied alcohol 



These results are necessarily incomplete, yet merit some dis 



cussion. 



factors which all these cases had in common 

 condition in which there was a tendency to an 



bic environment, and (2) citric acid-potassium citrate mixtures 



(with one exception — see Oosp 



Citri 



This semi 



anaerobic condition was obtained in the Aspergillus cultures 

 through stoppering the flasks with rubber stoppers and in the 

 other cultures by the mat tending to form (where there was a 

 mat formed) in the solution instead of on its surface as was usual 

 with most of the fungi used. Oospora grows in the solution in a 

 yeast-like manner; the two species of Alternaria and the Phomop- 

 sis, besides being slow growers, start under the surface of the 

 solution and eventually form a sponge-like mass which contains 



solution interstitially. Under such circumstances there is 

 ain to be a solution saturated with C0 2 and at the same time 



the 



probable shortage of O 



the slow diffusion from the 



the 



moderated condition of anaerobism in which 



there is an excess of CO t and a shortage of 2 would seem then 



be a primary factor. 



The question of carbon source is more complicated than 



