108 C. M. JACKSON AND C. A. STEWART 



In chart 5, the average body weight curves are shown for the 

 albino rats refed after underfeeding from three weeks up to 

 nearly a year (average 342 days) of age. Rats from sixteen 

 litters are included, with 10 test males, 11 test females, 10 con- 

 trol males, and 6 control females. In no case did the maximum 

 body weight of an individual test rat approach that of the 

 corresponding control of the same litter and sex (table 1). As 

 shown by the curves, the underfed rats grew rapidly for a time 

 after ref ceding, but were permanently stunted and unable to 

 attain the normal adult body weight, although amply refed 

 until growth had ceased. 



While there is clearly a permanent stunting in the body weight 

 of the rats as a result of the earlier period of underfeeding, it is 

 difficult to measure the amount of depression on account of 

 irregularities in the various curves, as shown in charts 1 to 5. 

 Measured roughly, however, it may be said that the shortage 

 in ultimate body weight in the test rats varies from about 10 

 per cent in chart 1 to about 35 per cent in chart 5. We may 

 consider the dwarfing effect of inanition in general as varying 

 according to, 1) the length of the underfeeding period; 2) the 

 age at which the inanition occurs; 3) the sex; 4) the severity, 

 and, 5) the character of the inanition. 



As to the length of the inanition, it is found, as might be 

 expected, that in general the longer the period of starvation in 

 the young animal, the more marked is the depression in ultimate 

 body weight. This is not so clear in charts 1, 2, and 3, as in 

 charts 4 and 5. The curves of Stewart ('16) show complete 

 recovery of rats fully refed after a period of maintenance (at 

 constant body weight) by underfeeding beginning at three 

 weeks and extending up to four, six, or ten weeks of age. (The 

 males at ten weeks formed an exception, which will be con- 

 sidered later) . The present experiments show that if the under- 

 feeding beginning in rats at the same age (three weeks) is ex- 

 tended up to twenty weeks, even allowing a moderate increase 

 in the body weight, there is a marked permanent depression 

 of the ultimate body weight, as shown in chart 4. If the under- 

 feeding is prolonged to nearly a year, the effect is still greater, 



