The more important results of the present investigation may be summarized as follows: The average daily gain in weight of the young rats refed after being held at constant body weight for short repeated periods was somewhat higher than that of the controls. This enabled the test rats to make up lost time and to overtake the controls, but not to exceed them in body weight. The average daily loss in weight did not increase in the rats on successive periods of severe fasting, involving a loss of 25 per cent. of the initial weight. The increment of body weight upon refeeding the test rats after each severe fast amounted to only about 16 per cent. of the ingested food (exclusive of water). The amount of food required daily for maintenance decreased during the first fifty days of the experiment, but after that time apparently no further diminution occurred. The growth in body weight of the rats refed after maintenance for various periods averaged for some time considerably higher than the normal for the (younger) controls of corresponding initial weight. Thus the stunted rats were able to overtake the full-fed controls in body weight before the end of the normal growth period. No effect of the stunting upon the ultimate body weight was noted. As to the body proportions, the relative weights of the head, trunk and extremities remain practically normal during the various periods of refeeding. Of the systems, the musculature and "remainder" continue practically normal for corresponding body weight during the various periods of refeeding. The integument rapidly increases, and the skeleton decreases, in relative weight, so that both reach approximately the normal proportions within the first two weeks of refeeding after maintenance from three to twelve weeks of age. The viscera which are known to lose weight during maintenance—thymus, spleen, thyroid, lungs and ovaries—likewise apparently regain their normal relative weight within two weeks after refeeding. The thymus, and possibly the lungs, spleen, and ovaries, are apparently even above normal (over-compensatory growth) at four weeks of refeeding, but all are found practically normal in the rats refed to the adult stage. The viscera whose weight remains nearly constant during maintenance—brain, heart, kidneys, liver, and epididymi—in general present approximately normal proportions during the process of refeeding; although the heart appears slightly above normal and the epididymi somewhat below. The viscera whose weight increases during maintenance—eyeballs, spinal cord, alimentary canal, hypophysis, testes and suprarenals—have in general decreased in (relative) weight so as to approach the normal within the first four weeks of refeeding. The testes and the suprarenals may even become subnormal in weight during the first four weeks of refeeding, but all are practically normal in the rats refed to the adult condition. The pineal body was approximately normal in weight in the test rats refed four weeks, and in the adult test animals. There was no evidence of a sexual difference in the weight of the pineal body in rats of corresponding body weight.