PRELIMINARY NOTE ON THE SIZE AND CONDI- 

 TION OF THE CENTRAL NERVOUS SYSTEM IN 

 ALBINO RATS EXPERIMENTALLY STUNTED. 



SHINKISHI HATAI, Ph.D. 



{Associate, The Wistar Institute oj Anatomy and Biology.) 



For these observations five litters of rats were so divided into 

 two groups that the average body weight was nearly the same in 

 both and one group was given the full laboratory ration, while to 

 the other was fed the minimal amount of bread, corns and cereals. 



The normally fed group constitutes the "first controls," and 

 the underfed rats, the "stunted group." For further comparison, 

 young rats with the approximately same body weight as the 

 "stunted group," but much younger, were taken for the "second 

 controls." 



Beginning at the age of thirty days, the underfeeding consider- 

 ably retarded the growth of the stunted group so that when they 

 were, on the average, 170 days old they weighed 91.5 grams, 

 whereas the "first controls" — of the same average age — weighed 

 146.5 grams. The younger rats from 80 to 100 days old which 

 formed the "second controls," weighed on the average 86.3 grams. 

 It must be remembered that during the time the behavior experi- 

 ments were carried on (for nearly thirty days), the experimented 

 rats were fed with normal diet and as a consequence these rats 

 gained somewhat rapidly in body weight. Therefore the pos- 

 sibihty of obtaining permanently stunted rats by means of under- 

 feeding is still undetermined. All the rats were killed and weighed 

 immediately after the behavior experiments were ended. 



The main results obtained from the present experiments are 

 exhibited in the following table. 



Exterjial characters.- — The most conspicuous external differ- 

 ences between normal and stunted rats as shown by the stunted 

 rats are in the length of the body and of the tail, both of which 



