548 



THE AMERICAN NATURALIST [Vol. LV 



those of the males. The values of K in the second cycles 

 were less than those in the first cycles. In the case of 

 males on adequate diet the value of K in the second cycle 

 is about 66 per cent, of its value in the first, but in the 

 females the value in the second cycle is only 33 per cent, 

 of that in the first cycle. 



The values of the constants are somewhat different in 

 the cases of rats subjected to an initial period of suppres- 

 sion. Eat No. 1012 reached approximately the same body 

 weight as a male rat fed continuously on adequate diet. 

 Its weight was 127 g. when full feeding began on the 

 368th day; the gain was, therefore, 153 g. in 212 days. 

 The male rats on adequate diet weighed 127 g. at the 77th 

 day; their gain of 153 g. was, therefore, made in 286 days. 

 The animal recovering from initial suppression, there- 

 fore, required considerably less time to make an increase 

 from 127 g. to 280 g., than adequately fed animals re- 

 quired to reach the same stage of development. 



The case of No. 2033 (female) has special interest be- 

 cauj^o of the remarkably long period of stunting. The 

 ])('ri()(l (if sui)pression started on the 39th day when the 

 i ;it wt iuhed 53 g. and ended on the 510th day when it 

 wciiiluMl g. The animal attained a w^eight of 222 g. in 

 135 days, following the resumption of full feeding. A fe- 

 male rat on adequate diet from the time of weaning would 

 require 295 days to increase from 57 g. to 222 g., or more 

 than twice the time to make the same gain. Other records 

 of the time required by stunted and by adequately fed an- 

 imnU to attain a given weight are given by Osborne and 

 Mciulel ' and in all cases the time was greatly reduced 

 in the case of animals recovering from stunting. These 

 authors likewise pointed out the broad biological signifi- 

 cance of this faster growth rate. This question of rate 

 is one of extreme interest in connection with the dynam- 



n O^horiu', T. II.. an. I :^IVn.|. I. I.. I',., J;,.- .. ./„//,-. f'husiul., 40: 16-20, 

 1916. 



