THE DIGESTIBILITY OF THE DASHEEN. 3 



were not restricted with respect to the amounts of the accessary foods 

 eaten. As a result the amounts of food eaten during the different 

 test periods varied quite materially. 



SUBJECTS. 



The subjects who assisted in this investigation were strong, healthy 

 men, with normal appetites and digestive functions, whose ages 

 varied from 20 to 40 years. With one exception they were all stu- 

 dents in local institutions. Since all had more or less muscular ex- 

 ercise, it seems fair to regard them as engaged in light muscular 

 work rather than as of sedentary occupation. Their normal dietary 

 was simple and, except that it contained meat, was not materially 

 different from that of the experimental periods and, accordingly, 

 the change from one type of diet to the other was not accompanied 

 by any noticeable physiological disturbances. The subjects were in- 

 structed to submit a report of their physical condition during the 

 experimental period and in every instance they stated that they were 

 in normal condition. Inasmuch as this study of the dasheen was 

 primarily concerned with the coefficients of digestibility, no attempt 

 was made to maintain a uniform body weight and no record was 

 kept of the weight of the subjects. The ration for each subject was 

 prepared and weighed in advance. They were instructed to reserve 

 any uneaten portions of the diet for analysis, and how to collect feces 

 resulting from the experimental diet. 



RELATION BETWEEN MATURITY AND DIGESTIBILITY. 



In addition to considering the general question of digestibility it 

 seemed desirable also to determine whether or not maturity of the 

 dasheen influenced their digestibility. Obviously, for this purpose 

 dasheens were needed which were as nearly alike as possible except 

 in respect to maturity at the time of harvesting. The Office of 

 Foreign Seed and Plant Introduction of the Bureau of Plant Indus- 

 try, accordingly provided representative samples of immature and 

 mature dasheens grown under controlled conditions at the plant 

 introduction field station, Brooksville, Fla. Rows which were ad- 

 judged to be typical of the field were chosen, and about six weeks 

 before the usual harvesting time the alternate plants were harvested 

 and their entire root systems forwarded to this laboratory as were 

 also the tubers of the remaining plants when later they were con- 

 sidered to be mature. The tubers in both cases were eaten less than 

 a week after being removed from the ground. 



