WEIGHTS OF ORGANS IN UNDERFED YOUNG RATS 



103 



and five or six times as heavy as those held at constant body- 

 weight from the age of three weeks (fig. 1). In addition, a 

 large number of observations upon the normal rat previously 

 pubHshed (by Donaldson, Hatai, Jackson, Lowrey and others) 

 are available for comparison. Of the animals used in this 

 experiment, the distribution of sexes is given in table 1. 



In table 2, the net body-weight (gross body-weight, including 

 intestinal contents, is slightly higher), of the animals used is 

 indicated. At each time period the average weight (and range) 

 for each sex is given, for both controls and test animals held at 

 constant body-weight. The cards containing the original in- 

 dividual records for all animals used will be deposited in The 

 Wistar Institute of Anatomy, where they may be consulted if 

 desired. 



The rats were kept in ordinary wire cages (with wire-net 

 bottoms, allowing the feces to drop through) and were individu- 

 ally weighed daily before feeding. Those under experiment 



Net 



TABLE 2 

 budy-ircight of rats whoi killed; average weight and range indicated 



