464 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



and the United States Railroad Administration has adopted, as 

 standard, the type of car which these investigations have shown to 

 be the most efficient. 



Tesl shipments were made of fruits and vegetables under ventila- 

 tion, and it was shown that heavy loads may be moved under venti- 

 lation with as low temperatures as light loads. 



Extensive investigations relative to the protection of perishable 

 shipments from frost damage in transit were conducted, and the data 

 obtained in this work show clearly the fundamental factors neces- 

 sary for satisfactory frost protection. During the summer of 1918 

 tests were conducted in cooperation with the United States Railroad 

 Administration to determine the best methods of constructing heater 

 cars. 



Demonstrations were made to railroad officials, growers, and ship- 

 pers in many sections of the United States regarding the possibility 

 of frost protection, and the relation of loading methods, car construc- 

 tion, insulation, and refrigeration to decay and deterioration in fruit 

 and vegetable shipments. 



Serious damage has been caused in the past by improper methods 

 of loading shipments of fruits and vegetables. Investigation of this 

 problem was begun in the fall of 1917 and continued throughout the 

 season, and demonstrations of the factors to be considered were made 

 both at shi]:)i)ing and market centers. This work has resulted in the 

 adoption of regulations by shippers and railroad officials which will 

 undoubtedly reduce losses from poor loading. Particular ernphasis 

 was placed on demonstrations designed to show the possibility of 

 loading perishable shipments more heavily. 



Investigations have been made of the factors governing the success- 

 ful storage of fruits and vegetables, and the results of these studies 

 have been made the basis of demonstrations. In the West and 

 Pacific Northwest more than 100 common storage houses for apples 

 have been constructed or remodeled in accordance with the plans or 

 suggestions of this bureau. Important improvements have been 

 effected in the construction, ventilation, and management of houses 

 and cellars intended for the storage of Irish potatoes, and plans were 

 completed for the erection, in accordance with this bureau's recom- 

 mendations, of several hundred sweet-potato storage houses during 

 the summer and fall of 1918. 



MAKKETING DAIRY PRODUCTS. 



Investigations regarding the marketing of dairy products which 

 were started in 1914 were continued during the fiscal year 1918, under 

 the direction of Mr. Roy C. Potts. 



An investigation of the economic problems arising in connection 

 with the marketing of fluid milk in the larger and more important 

 cities in the United States was completed and the operation of milk 

 producers' marketing associations was studied, assistance being given 

 in improving their methods of marketing. Particular consideration 

 was given to those associations which operated distributing plants. 



Studies were made in a number of cities regarding the supply of 

 and demand for fluid milk and cream, butter, eggs, and cheese, with 

 the view to outlining definite plans for the establislmient of a market 

 reporting service. 



