15 



PHYSIOLOGICAL CHEMISTRY. 



he work done under this head includes two sections, one on animal 

 and one on vegetable physiology, the former being in charge of 

 F. C. Weber and the latter under J. A. Le Clerc. The work in the 

 former section includes the conduct of the experimental food table 

 for determining the effects on health and digestion of various food 

 preservatives and food colors, together with experimental work to 

 improve methods of analysis ordinarily employed in physiological 

 work. It is the intention to extend this work to digestion experi- 

 ments on the lower animals. 



Metabolism and feeding experiments are conducted on the lower 

 animals, using in the former organic and inorganic forms of phos- 

 phorus and sulphur, and in the latter various prepared foods and 

 different carbohydrates to determine their nutritive value. Studies 

 of enzyms and their application to chemical and physiological methods 

 of analysis are also included in this line of work. Cooperative work 

 for the Association of Official Agricultural Chemists on meat and fish 

 is done in this laboratory, the chemist in charge acting as referee. 



The investigations in vegetable physiological chemistry include 

 cooperation with the various divisions of the Bureau of Plant Industry 

 in studying the chemistry of growing plants, the composition of cereals 

 and cereal products, grown under different conditions of environment, 

 and with respect especially to moisture and fertilizing constituents, 

 both in the greenhouse and in the fields. Other studies include the 

 chemical, physical, and physiological changes taking place in barley 

 during germination, the changes in the composition of cereals during 

 storage, and methods of analysis related to such work. 



BACTERIOLOGICAL CHEMISTRY. 



This investigation, under the direction of George W. Stiles, jr., 

 consists principally of the bacteriological examination of various food 

 materials, together with the inspection of methods of handling and 

 preparation, including milk, cream, ice cream, water, uncooked vege- 

 tables, and shellfish; also the bacterial 'content of fowls, fish, eggs, 

 beef, game, etc., as affected by storage. 



Considerable attention is devoted to testing the germicidal, anti- 

 septic, and preservative value of certain drugs, chemicals, and fruit 

 juices. Special consideration is also given to the identification and 

 classification of the various bacteria, yeasts, and molds encountered 

 in these investigations. Another line of work involves the exami- 

 nation of surgical dressings, gauzes, ligatures, etc., to determine their 

 sterility. Cooperative work with other laboratories is done when 

 required. 



[Cir. 14] 





