146 ANNUAL, REPORTS OF DEPARTMENT OF AGRICULTURE. 



treatment of the soil to lit it for dry-land crops, the kind of 

 crops best suited to newly reclaimed marshes, the cost of reclama- 

 tion, and the profitableness of the reclamation. Very full data 

 were obtained on nearl}'' all these points. The investigations along 

 the Delaware River were supplemented by examinations of re- 

 claimed lands on the coast of New England, Nova Scotia, and New 

 Brunswick. 



NUTRITION INVESTIGATIONS. 



In continuing studies of the nutritive value of animal and vegetable 

 products used as food, attention has been directed particularly to two 

 lines of work, namely, the use of cheese and other materials as pos- 

 sible substitutes for meat in the diet, and the adaptation of the respi- 

 ration calorimeter to studies of physiological changes in vegetable 

 products, particularly with reference to the changes which bananas 

 undergo during the active ripening period. 



The work with cheese and other meat substitutes has involved respi- 

 ration calorimeter experiments on the relative ease of digestion of 

 cheese and meat, as well as more practical experiments, the general 

 conclusion being that if a housekeeper so desires it is possible to pre- 

 pare a well-balanced dietary in which cheese and other foods may be 

 used wholly or in part in place of meat. The question has been dis- 

 cussed at length in an article in the Yearbook, while much related 

 information on the use of cheese in the diet has been prepared for 

 publication as a Farmers' Bulletin. 



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 they 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 the study 

 of technical questions. 



OFFICE OF PUBLIC ROADS. 

 THE EVOLUTION OF THE ROAD PROBLEM. 



The United States is in the midst of a national readjustment with 

 regard to road improvement. The rapidly changing traffic conditions 

 have necessitated equally radical departures from the old methods of 

 road construction and maintenance. Methods which but a few years 



