ANNUAL REPORT, 1937 47 



1937 than for several years previous, but was not sufficiently abundant to be 

 destructive. As the season advanced, leafy shoots ceased to be affected, but the 

 disease continued to affect the flower and fruit clusters up to the time that the 

 fruits ripened, when typical "mummy" berries developed. A hybrid variety not 

 grown commercially was worst affected. The disease also occurred to a consid- 

 erable extent on Cabot and Pioneer. 



DEPARTMENT OF DAIRY INDUSTRY 

 J. H. Frandsen in Charge 



Nutritive Value of Chocolate Flavored Milk. (W. S. Mueller and W. S. Ritchie, 

 Department of Chemistry.) Some of the results of this investigation have been 

 published in the Journal of Dairy Science, 20 (6): 359-369, 1937. 



The results of the previous year on the effect of feeding varying percentages of 

 cocoa to white rats were checked on 16 male rats. At the end of six weeks the 

 average gain of the rats on the various diets was as follows: No cocoa, 60.5 grams; 

 1 percent cocoa, 60 grams; 2.5 percent cocoa, 55.2 grams; 4 percent cocoa, 47.7 

 grams. These results confirm the previous findings. 



In another experiment Dutch and American process cocoa were compared. 

 Only one level of cocoa, 4 percent on a fluid milk basis, was fed. In addition to 

 minerals and cane sugar, all of the diets contained 2 percent by weight of dried 

 brewers' yeast, and two drops of cod liver oil were added daily to the ration. 

 Twelve males and fifteen females were used in this experiment. 



The average gain after six weeks was as follows: 



No cocoa (control) 64 . 5 grams 



Dutch process cocoa 65 . 3 grams 



American process cocoa 60. 5 grams 



The rats receiving the American process cocoa did not do quite so well as those 

 receiving the Dutch process cocoa. However, the most striking result from this 

 experiment was the fact that there was no retardation in growth of the rats on the 

 4 percent Dutch process cocoa, as in previous experiments. As expected, the 

 consumption of cocoa per day increased slightly when the diet was supplemented 

 with yeast and cod liver oil. Since larger quantities of cocoa reduce the palatability 

 of milk until the zero point is reached, it may be that this explains the observed 

 lack of growth in the earlier experiments, rather than that the cocoa exerts a 

 toxic effect. This phase of the problem is receiving further study. 



Urine analysis. In order to secure information on the physiological action of 

 cocoa, urine analyses were made. Samples over a period of 24 hours were col- 

 lected from 12 animals, four rats on each of the following diets: No cocoa, 4 percent 

 Dutch process cocoa, and 4 percent American process cocoa. The average results 

 for five trials are given in the following table: 



Kind of Volume per Specific Acidity Uric Acid 



Cocoa day c.c. Gravity c.c. .1 pH mg per 



NaOH 



c.c. 



No cocoa (control) ... . 4.6 1.043 2.3 6.72 0.2064 



Dutch process cocoa .. . 5.7 1.037 2.6 6.49 0.1913 



American process cocoa 5.6 1 . 034 2.4 6 . 45 . 2023 



