GROWTH AFFECTED BY FEEDING DUCTLESS GLANDS 313 



the amounts fed) had no effect upon the weight of the female 

 albino rats in this experiment. 



A graphic representation of the growth of the 'higher dosage' 

 group of females is shown in chart 3. The body weights in 

 all cases remain close to those of the controls (muscle-fed). In 

 the 'higher dosage' groups, the body weights (chart 1) are seen 

 to be much higher than the normals of Jackson and also of Don- 

 aldson (excepting near the end of the experiment). In the 'lower 

 dosage' groups the body weights average lower, more nearly 

 comparable to the normals of Jackson and Donaldson. This 

 difference in body weight between the 'higher dosage' groups 

 and the 'lower dosage' groups is not due to the different amounts 

 of ductless glands fed, however, as a similar difference is shown 

 by the controls in each group. A careful study of the growth 

 of individuals within each litter shows that in nearly every in- 

 stance those rats which at three weeks were larger (or smaller) 

 than the controls retained the same relative position as regards 

 body weight throughout the experiment. 



The male albino rats to which ductless glands were fed also 

 seemed not to be affected in body weight by the treatment. 

 A careful study of table 7 and chart 4 shows nearly the same 

 facts for the male rats as have just been stated for the females. 

 The weights of the different 'higher dosage' groups are unusually 

 close together at 70 days of age, except in the case of the pineal- 

 fed. The 'higher dosage' pineal-fed animals at this age are 16.5 

 grams lighter in weight than the controls; but this difference 

 is not great, and as this group averaged less in weight than the 

 controls at the beginning of the experiment, the difference in 

 weight between the two is probably due to normal variation. 

 In the 'lower dosage' group, the pineal-fed are slightly above 

 the controls in weight. After 70 days of age many rats were 

 autopsied and hence the groups are no longer directly com- 

 parable, but individuals of the same litter were compared with 

 each other and showed the same results as in the case of the 

 females. On the whole, there appears to be no evidence indi- 

 cating that the ductless gland feeding has naterially affected 

 the body weight in any case. The differences are inconstant, 

 and well within the limits of the variability to be expected. 



