152 C. M. JACKSON 



the muscular system shows the strongest growth capacity, and 

 increases with greater relative rapidity than any other system 

 (Jackson and Lowrey) . The skeleton is of course growing stead- 

 ily, but at a much slower rate, so that it is decreasing in relative 

 (percentage) weight. Under the adverse nutritive conditions 

 in young animals when the body-weight is held constant, how- 

 ever, the musculature is barely able to maintain its weight, 

 while the skeleton is able to absorb more than its share of the 

 available nutrition, and to grow steadily (though at a retarded 

 rate). There are similar differences among many of the indi- 

 vidual organs, though in some cases (e.g., liver, alimentary canal) 

 there is a certain degree of parallelism between the normal growth 

 tendency and the behavior when the body-weight is held con- 

 stant at corresponding periods. 



That also the power of maintenance may vary in organs 

 according to the nutritional conditions is shown by the char- 

 acteristic differences in the losses of organ-weight in chronic 

 inanition as compared with acute inanition in adults (Jackson 

 '15 a, '15 c). 



Finally, it should be remembered that the results of the 

 present paper, as well as those concerning adult chronic inanition 

 in a previous paper (Jackson '15 c), are based upon the use of a 

 diet wholesome and balanced, but insufficient in quantity. It 

 is probable that more or less different results would follow 

 from other forms of inanition, such as 'partial inanition' from a 

 chemically defective or highly unbalanced diet. For example, 

 Hatai ('15) finds a pronounced atrophy of the testis and other 

 characteristic changes in albino rats whose growth had been 

 retarded by a 'lipoid-free' ration. Bowin ('80), however, in 

 dogs and rabbits fed dry food only (no water) found, with a 

 loss of about 50 per cent in body-weight, the losses in organ- 

 weight similar to those following total hunger. 



