6 



BULLETIN" 601, U. S. DEPABTMENT OF AGBICULTUBE. 



the thermometers was about 40° F. It has been determined that 

 this point is about as low as the ice in the bunkers will hold the load. 



TREATMENT OF EXPERIMENTAL LOTS. 



As has been stated, the precooled car contained an experimental 

 lot consisting of an equal number of hampers of lettuce carefully cut 

 and commercially cut from the same field at the same time. An 

 exactly similar lot was shipped at the same time in a refrigerator 

 car that was not precooled. The two cars went to the same market, 

 in most cases to New York City, where a representative of the Depart- 

 ment of Agriculture inspected them upon their arrival and again 

 three days later. 



Comparable lots, both precooled and nonprecooled, were held at 

 Palmetto in an iced refrigerator car and kept under approximate 



Fig. 4. — Two heads of lettuce, showing the difference in methods of cutting: A, Commercially cut 



B, carefully cut. 



transit temperature conditions. It was possible to keep the tempera- 

 tures in this holding car under close control, so that these lots give 

 a good index of the effect of temperature on the development of 

 decay. Six days after cutting — the average length of time required 

 for the cars to reach the principal northern markets — the lettuce was 

 removed from the holding car and inspected. It was then held at 

 ordinary temperatures for three days and again inspected. Accurate 

 records were kept as to the general condition of the lettuce and the 

 amount of decay at each inspection. 



RESULTS OF EXPERIMENTS IN 1913-14. 



SHIPPING LOTS. 



During the season of 1913-14 nine full comparable experimental 

 lots were shipped to northern markets and 16 lots were held in 

 Palmetto. The following tables and diagrams give a summary of 



