108 



BULLETIN 77, HAWAII EXPERIMENT STATION 



ride 1 percent, cornstarch 57 percent, Crisco 10 percent, viosterol to 

 supplv 1 part in 40,000 parts of diet. 



Despite the fact that the young rats were placed on the A- free diet 

 at from 19 to 21 days of age, when they weighed an average of 41 

 grams, they made large gains before the vitamin A stores were depleted, 

 reaching an average weight of 124 grams. The average time of deple- 

 tion was 31 days. Previous experiments showed that rats fed 3 units 

 of carotene (International Standard) per day (6 days a week) suffered 

 such high mortality that 4 units was chosen as the standard of compari- 

 son. Rats fed this quantity of carotene, and even those fed 3 units, if 

 they survived, showed such great increments in weight that the results 

 cannot be compared with the recommended Sherman standard — a gain 

 of 3 grams per week (62, p. 265). 



After the depletion of vitamin A stores the rats were fed the supple- 

 mentary foods for 5 or 6 weeks. From each litter of rats were chosen 



1 negative control which was continued on the basal diet only and 2 or 

 more positive controls which were fed 4 units of the 1931 International 

 Standard carotene (1 unit is equivalent to 0.6 gamma of carotene). 

 With few exceptions there was good distribution of the sexes within the 

 various groups — positive and negative controls and animals fed the 

 fruits. Daily feedings (i.e., every day except Sunday) were given in 

 the case of most fruits ; carotene was fed 2 times a week, papaya and 

 pohas 3 times a week. For all vitamin tests of the fruits, quantities of 



2 grams or more were weighed on a Torsion balance and quantities less 

 than 2 grams on a chainomatic balance. The results of feeding caro- 

 tene, figs, guavas, papayas, pineapples or pohas as the sole source of 

 vitamin A are summarized in Table 11 and Figure 14. 



Vitamin B: For the vitamin B experiments, young rats were weaned 

 at from 17 to 18 days of age and continued on the breeding diet to 21 

 days, when thev averaged 40 grams in weight. They were then placed 

 on the following diet: extracted casein (62, p. 100) 18 percent, salt 

 mixture 4 percent, cod liver oil 2 percent, butter fat 8 percent, corn- 

 starch 53 percent, autoclaved yeast (Northwestern yeast autoclaved at 

 15 lbs. pressure for 5 hours) 15 percent. The average time for deple- 

 tion was 23 days when the rats weighed on the average 72 grams. From 

 each litter of rats were chosen 1 or more negative controls which were 

 continued on the basal diet only and 2 or more positive controls which 

 were fed 0.005 gram of the 1931 International Standard (0.010 gram 

 of the International Standard is equivalent to 1 unit. The standard is a 

 concentrated preparation of the anti-neuritic vitamin, adsorbed on kaolin 

 from a watery extract of rice polishings and subsequently dried). 

 Supplements of fruits were fed daily except Sunday. The International 

 Standard was fed as 0.01 gram three times a week. Table 12 and Fig- 

 ure 15 summarize the results cf feeding the International Standard, figs, 

 guavas, papayas, pineapples, soursops or tamarinds as the sole source of 

 vitamin B. 



Vitamin G (B 2 ) : For the vitamin G experiments, young rats were 

 weaned at from 17 to 18 days and continued on the breeding diet an 

 average of 22 days, when they averaged 43 grams in weight. They were 



