ANNUAL REPORT, 1939 41 



the flower buds were just ready to open, and the second when the petals had 

 fallen from most of the flowers. The results are shown in the table. 



The degree of rot control obtained by the use of the several spray mixtures was 

 greatest during the period from October 1 to November 1 and thereafter declined, 

 sometimes markedly so, because of an acceleration in the rate of spoilage of the 

 berries from so many of the sprayed plots after November 1. The acceleration in 

 the rate of spoilage after November 1 seems not to be correlated with spray 

 treatment, as the same thing was observed in berries from one or more plots 

 sprayed with any one of the several spray mixtures used and also in berries from 

 plots not sprayed. In some instances it appeared to be correlated with local 

 conditions on the bog but this could not be established in all cases. 



Blueberry Disease Investigations. (H. F. Bergman and W. E. Truran.) Isola- 

 tions of a fungus causing "wilt" on two bushes of unselected hybrids at the State 

 Bog were made at intervals during the growing season. Both bushes are badly 

 diseased and are known to have been diseased for the last three years at least. 

 Phomopsis was isolated consistently from both diseased leaves and stems and 

 appears to be^^tihe causal organism. 



DEPARTMENT OF DAIRY INDUSTRY 

 J. H. Frandsen in Charge 



Nutritive Value of Chocolate Milk. (W. S. Mueller and N. L. Keyock.) The 

 nutritive value of chocolate-flavored milk is being studied by animal experimenta- 

 tion. A chocolate syrup which is practically free from theobromine, cocoa fiber, 

 and cocoa fat was compared with a product which contains these substances in 

 ordinary amounts. In both cases the chocolate milk was made from one part of 

 syrup to ten parts of fluid milk (3.5 to 4.0 percent butter fat). Plain milk served as 

 an additional control. Three groups of eight rats each were fed for five weeks. 



In general, the rats on the plain milk and those on the special chocolate milk 

 were the extremes, with the rats on ordinary chocolate milk about midway 

 between. The rats on the plain milk diet gained least in weight, were the most 

 active, excreted the most urine, and the pH of the urine was lowest. Here, however, 

 the consistency ends, for the rats on the ordinary chocolate milk showed a slightly 

 higher acidity of urine than the plain milk group, while the figure for the rats on 

 the special chocolate milk was very much lower. The figures for specific gravity 

 of urine were highest for the plain milk group and lowest for the rats on the 

 ordinary chocolate milk. 



More data are necessary before the results can be interpreted. 



The Effect of Cocoa upon the Digestibility of Milk Proteins. (W. S. Mueller 

 and L. D. Lipman.) The purpose of this study was to determine whether or not 

 the addition of cocoa had any adverse effect on the digestibility of milk proteins. 

 Both "in vitro" and animal feeding have been used in this study of three different 

 cocoa powders: a Dutch-process, an American-process, and a blend of Dutch 

 and American cocoa powders. 



Experiments in vitro showed that, as the concentration of the cocoa blend 

 was increased from 1 to 2.5 to 4 percent, the digestibility of the milk proteins 

 was reduced 3.1, 8.2, and 12.4 percent, respectively, after four hours' digestion. 

 The addition of 4 percent Dutch cocoa or American cocoa reduced the digestibility 

 of the milk proteins 11.8 and 13.7 percent, respectively. As the percentage of 

 butter fat was increased from to 2 to 4 percent, the digestibility of the milk 

 proteins of a chocolate milk containing 4 percent of American cocoa was reduced 



