Scientific Proceedings (114). 



trial. The vitamin-bearing substances were the only noteworthy 

 sources of either fat or carbohydrate, and supplied 4-8 per cent, 

 of the food eaten. Whether rats will attain adult size and normal 

 function on such diets, furnishing protein as the almost exclusive 

 source of energy and tissue substance, remains to be determined 

 further. If future experiments prove as successful as those here 

 described various problems of nutrition and physiological function 

 can be approached from new experimental standpoints. 



80 (1662) 



The addition of yeast to a milk diet. 



By PHILIP B. HAWK, CLARENCE A. SMITH, and OLAF BERGEIM. 



[From the Laboratory of Physiological Chemistry, Jefferson Medical 

 College, Philadelphia.] 



The experiments were made on white rats, one group of rats 

 being fed a diet of pasteurized milk and a second group being fed 

 a milk and yeast diet. The rats receiving the yeast made more 

 satisfactory growth gains than did the rats receiving no yeast. 

 Inasmuch as milk has been shown to be low in the water-soluble 

 "B" vitamine, which is present in high concentration in yeast, 

 it would seem that yeast may be found to be an important dietary 

 adjunct for use in baby feeding. 



81 (1663) 



The rate of fixation of complement at various temperatures. 



By R. L. KAHN. 



[From the Bureau of Laboratories, Michigan Department of Healthy 

 Lansing, Michigan.] 



This investigation embraces three types of complement-fixing 

 substances: (1) those elicited in rabbits due to injection of purified 

 proteins; (2) those produced in the same animals due to injection 

 of bacteria, and (3) those found in the serum of syphilitic patients. 

 The antigens employed in the first two cases were specific, while 



