712 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



enters the respiration chamber, of the teniperatnrc of the water cur- 

 rent which carries out tiie heat liberated in the chamber and a device 

 for securing automatically a continuous record (;f the temperature 

 ditl'erence of this water current as it enters and leaves the chamber; 

 in other words, the measurements of factors fundamental to the de- 

 termination of the energy output of the subject are made auto- 

 matically ami continuously with an accuracy which could not be 

 reached hitherto. At the same time the labor of conducting the 

 experiments has been greatly lessened, a matter of much importance 

 in experiments which may continue uninterruj^tedly for a number of 

 days at a time. Some of the improvements in the respiration calo- 

 rimeter have been noted in the description of it in its present form, 

 which appeared in the Yearbook of the department for 1910. 

 Others, together with an outline of new lines of work, have been 

 briefly described in a more recent publication.* 



Particularly interesting is the adaptation of the respiration calo- 

 rimeter to the study of problems of vegetable physiology, and the 

 results obtained in a series of experiments carried on in cooperation 

 with the Bureau of Chemistry on the respiration and energy output 

 of bananas during the active ripening period. Not only have the 

 results provided facts of great value in connection with studies of 

 ripening fruit which the department is carrying on, as well as facts 

 of theoretical interest, but have also shown that the respiration 

 calorimeter offers a new means for studying problems of vegetable 

 physiology, which are of great importance to the producer and ship- 

 per of agricultural products, the warehouseman, and those who store 

 products in the home, as well as to the student interested in technical 

 questions. 



The work of collecting and editing data on food and nutrition 

 topics has been continued, as has also the preparation of material for 

 publication in the Experiment Station Record and in Experiment 

 Station Work. An increasingly large amount of time is required 

 for providing data on nutrition and related topics requested by 

 housewives, teachers, and other correspondents. 



During the fiscal year a technical bulletin, entitled Calcium, Mag- 

 nesium, and Phosphorus in Food and Nutrition, has been published, 

 as well as a series of 15 colored food and diet charts. A Farmers' 

 Bulletin on The Care of Milk and Its Use in the Home has been 

 issued in cooperation with the Bureau of Animal Industry. A cir- 

 cular on Food Customs and Diet in American Homes has been pub- 

 lished, as well as two articles already referred to, which have ap- 

 peared in the Yearbook of the department, and numerous summaries, 

 which have appeared in annual reports and similar publications. 

 There has also been prepared for publication during the fiscal year 

 a technical bulletin and two popular bulletins. Since the food and 

 diet charts of the department were published there has been much 

 demand for a descriptive bulletin for use in connection with them, 

 and such a bulletin is being prepared and is nearly completed. Much 

 work has also been done in the editing of other bulletins, both popu- 

 lar and technical and preparing them for publication. 



During the next fiscal 3ear it is proposed to continue the work 

 with cheese and meat already in hand, in so far as this seems neces- 



» Experiment St.itioD Record, 24 (1911). No. 7, pp. 601-606. 



