1923] 



CAMP — CITRIC ACID AS A SOURCE OF CARBON 



289 



sixteenth day under the same conditions. If no citrate were 

 used the growth curve for solution 2, at its peak, would be expected 

 to be about one-fifth the height of that for solution 1. As a 

 matter of fact it is a little better than that and the peak is main- 

 tained instead of falling off as it did in solution 1. The curves 



4 



JnTnl r.nrhnrx 



5 



TnTn I d*i fm.<. ? 



4 



J 



I 



V 



CJt/i Scl'n. I 



Fig. 20. Seclrotinia Liberliana in solution 1. 



Fig. 21. Sclerohnia Liberliana in solution 2. 



for the analyses indicate that a little citrate was used though 



great deal. 



In the analytical curves for 



the "loss of 



dextrose ' ' and ' ' loss of carbon ' ' curves follow each other 



and in solution 2 the "loss of carbon 



dextrose 



rises more rapidly than does the curve calculated from the titra- 

 tions. The conclusion from the above circumstances is that the 

 salt (in toto), as well as the free acid, was being used. 



Phomopsis Citri. — The growth curves for organism 5 are given 

 in fig. 19. The analytical curves are not given, as they held noth- 



