218 ANNUAL EEPORTS OF DEPARTMENT OF AGEICULTUEE. 



Department of Agriculture Bulletin 568, " The Presence of Arsenic 

 in Hops," and Bulletin 666, "The Effect of Alkali Treatment on 

 Cocoas," have been issued. 



In connection with a study of the adulteration of " soft drinks," 

 a paper has been published on gingero], the pungent principle of 

 ginger, and on paradol, the pungent principle of grains of paradise. 



The results of studies on the fertilizing value of stable manure 

 treated with borax to destroy the larva of the house fly have been 

 made public, under the title " Boron : Its Effect on Crops and Its Dis- 

 tribution in Plants and Soils in Different Parts of the United States " 

 and " The Effect of Three Annual Applications of Boron on Wheat." 



Articles upon the occurrence of manganese in insect flowers and 

 insect flower stems, and also upon the effect of sodium nitrate applied 

 at different stages of growth on yield, composition, and quality of 

 wheat have been printed. An investigation upon the reduction of 

 nitrates by seedlings has been completed. 



A new method for the separation of the coloring substance from 

 leaf greens has been devised, and spectroscopic studies have been 

 made upon these color compounds. The determination of the compo- 

 sition of many of the salt-bushes and their allies has been completed. 

 The data will be published in order to give information concerning 

 the food value of these important forage plants of the semiarid 

 Southwest. 



CHEMISTRY AND NUTRITIVE VALUE OF PROTEINS. 



As part of a study to establish criteria for judging the suitability 

 of gelatins for food purposes, physico-chemical studies have been 

 made of gelatin, some of the results of which are in preparation for 

 publication. Complete hydrolyses have been made of kafirin, the 

 chief protein of kafir, and of arachin, the chief protein of the peanut. 

 The data have been published. 



The results of the chemical examination of the globulin of buck- 

 wheat and of stizolobin, the globulin of the Chinese velvet bean, 

 Stizolobium niveum, have been published. Stizolobin contains all 

 the necessary basic amino-acids, and feeding experiments with the 

 protein of the Chinese velvet bean have shown that this is biologically 

 complete and is properly utilized by animals. A study of the relative 

 nutritive values of many other kinds of beans was begun. 



A chemical examination of the globulin of the coconut is in 

 progress. This globulin, which constitutes most of the protein in the 

 coconut, contains all of the basic amino-acids necessary for normal 

 growth. Feeding experiments in progress with coconut press cake, 

 and the isolated globulin of the coconut indicate that both the press 

 cake and the globulin are biologically complete. This study is 

 timely, since the copra-crushing industry is assuming much impor- 

 tance in the United States, and there is a great demand for coconut 

 oil in its rapidly growing use in preparing the so-called butter sub- 

 stitutes. The feeding value of copra cake does not seem to be appre- 

 ciated as yet in the United States. A proper appreciation of this 

 feed by dairymen will assist in keeping a copra-crushing industry in 

 the United States after the war. 



