460 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



artificial pancreatic juice were employed. No silver went into 

 solution in any of the experiments. 



A number of extracts were examined to determine whether they 

 were of animal or vegetable origin, the diirerentiation of yeast 

 extract from vegetable or plant extracts forming a part of this 

 study. The identification of importations of canned meat was 

 attempted, especially to determine whether they were composed of 

 beef or of whale meat. 



Some work was also done on the determination of glycogen in 

 meat and on the analyses of culture media. The work on the analy- 

 sis of beef and yeast extracts of known origin was published in 

 circular form. A chart showing the composition of foods used for 

 infant feeding was compiled from the data on hand and from the 

 literature to be used as an exhibit at conventions and societies 

 interested in this subject. 



PLANT PHTSIOLOGICAL CHEMISTRY. 



The investigations in plant physiological chemistry have consisted, 

 as in previous years, of the study of the influence of environment, in 

 its broadest aspect, upon the character of plant growth, and this 

 laboratory has been occupied to a large extent in carrying on investi- 

 gations in collaboration with the various offices of the Bureau of 

 Plant Industry. 



These collaborative studies are as follows: 



(1) The study of the influence of environment on the chemical com- 

 position of the various cereals. The field work is under the immediate 

 direction of the office of grain investigations and the chemical work 

 is carried on by this laboratory. The grains under investigation are 

 wheat, rye, oats, barley, buckwheat, emmer, spelts, milo, kafir, durra, 

 etc. The work consists chiefly in growing diflerent varieties of these 

 grains in difl"erent localities. In this way it is hoped that valuable 

 results will be obtained. Already thousands of analyses have been 

 made, and a report of the work is in progress. During the past year 

 alone over 600 samples have been received from the office of grain 

 investigations. 



(2) The analysis of wheat grown under special conditions of sun- 

 shine and shade. The physicist of the Bureau of Plant Industry has 

 direct charge of these experiments. By the use of new and ingenious 

 apparatus it is hoped to be able to determine the action of the solar 

 rays in influencing the composition of wheat. 



(3) The continuation of the study of plants grown in the Great 

 Plains area. The office of dry-land agriculture of the Bureau of 

 Plant Industry is conducting an extensive series of experiments on 

 the influence of rotation on crop production and samples are fur- 

 nished this laboratory for the purpose of determining, if possible, the 

 effect on the chemical composition of the different methods of han- 

 dling growing crops. 



(4) The study of the composition of many varieties of barley grown 

 in the same locality for a series of years. For the past three or four 

 years the experiment station at St. Anthony Park, Minn., has been 

 conducting variety tests of barleys with the cooperation of the Bureau 

 of Plant Industry. Samples have been furnished this laboratory for 

 the purpose of determining the differences in the composition of these 



