28 CHESTER A. STEWART. 



of the controls, but this was probably due to chance variation, 

 and does not indicate an actual stunting of the test rats. The 

 females show complete recovery. 



Aron ('14) .noted no permanent stunting effects on the body 

 weight in young rats underfed less than 150 days. Osborne and 

 Mendel ('15, '16) have likewise observed attainment of normal 

 adult body weight after suppression of growth during a period 

 equal to or exceeding the normal growth period. One female 

 (2033) stunted by feeding on a limited quantity of food after the 

 age of 513 days increased from 59 grams to 222 grams in body 

 weight. Osborne and Mendel ('16) in their rats refed after 

 extended periods of growth suppression note a marked tendency 

 even to exceed the normal ultimate body weight observed by 

 King ('15). 



In my experiments, the inanition period was begun in rats at an 

 earlier age (3 weeks) than in the investigations just mentioned. 

 Even in these very young rats, however, the recovery in body 

 weight is usually complete, upon refeeding after maintenance 

 periods of one to seven weeks. 



The experiments of Briining ('14), however, indicate that stunt- 

 ing produced by subjecting newborn rats to repeated periods of 

 fasting during the normal nursing period may persist, at least 

 until fifty-four days of age, the test animals usually showing no 

 tendency toward compensatory overgrowth when placed upon 

 an artificial mixed diet. Whether or not complete recovery 

 might occur later was not determined. 



2. Ratio of Tail Length to Body Length (Table IV.}. 



Jackson ('15) noted that in young albino rats held at constant 

 body weight, the ratio of the tail length to the body length 

 increases from an average of .66 (normal) at three weeks to .84 

 at ten weeks. In the two rats killed at the end of nine weeks of 

 maintenance the tail-ratio (Table IV.) was .93 and .89, which 

 shows that in my rats the tail likewise became relatively long 

 during the inanition period. 



At the end of each period of refeeding (Table IV.), the average 

 tail-ratio, in the test rats (with two exceptions) ranged between 

 .80 and .84, which is a little below the normal for rats of corre- 



