112 C. M. JACKSON AND C. A. STEWART 



females in charts 1, 2, and 3, if all the controls had borne young 

 and all the test rats were virgins. As shown in the table above, 

 however, this was not the case, although pregnancies were con- 

 siderably more frequent in the control rats. In the rats which 

 had undergone prolonged inanition (charts 4 and 5), pregnancy 

 occurred very rarely, as above shown, but in these the excess 

 weight of the control is far greater than could be explained by 

 their bearing of young. It is evident, however, that if the fe- 

 male control rats had borne no young their weight would have 

 been slightly less and therefore somewhat nearer to that of the 

 test rats. The contrast between the results in male and female 

 emphasizes the difference between the sexes in their depression 

 of ultimate body weight as a result of an early period of 

 underfeeding. 



The question as to whether the dwarfing of the body produced 

 by inanition could be transmitted by heredity (in the few cases 

 where reproduction occurs) is of considerable interest. In the 

 present series, however, records are available only in the case of 

 the one female (St. 41.4) which bore young after the long under- 

 feeding period (3 weeks to 310 days). This extreme case might 

 be expected to show such an effect if any were possible. This 

 female reached a maximum of only 138 grams in bodyweight. 

 Mated with a normal male (of the same litter) , she bore two lit- 

 ters. One of these, litter no. 133a, was kept under observation. 

 The litter included four males and two females, of normal size 

 at birth. One male died early; the others reached adult maxi- 

 mum body weight of 215, 226, and 244 grams. The two females 

 reached maximum of 174 grams and 204 grams, both being preg- 

 nant at the time. Thus they were slightly below the normal 

 maximum weight, and each bore only one litter, but this is not 

 unusual even among the control rats (table 1). The two fe- 

 males and one male were alive and apparently normal at fourteen 

 months of age. The results therefore do not indicate the trans- 

 mission of any marked hereditary effect of inanition, though 

 further observations would be necessary to establish any definite 

 conclusion on this point. The result might of course be slight, 

 but cumulative in successive generations. 



