EFFECTS ON THE HYPOPHYSIS 45 1 



staining reactions) of the hypophysis cells. Unfortunately no details are given 

 as to the exact character and extent of the chronic inanition. Possibly his 

 negative results may be due to the comparative mildness of the inanition. 



Gans ('15) observed no abnormality in the hypophysis of puppies which 

 were underfed or malnourished on inadequate diets. 



The changes in the weight of the hypophysis during inanition have been 

 most extensively studied in the albino rat (Table 4). In adult albino rats 

 subjected to acute inanition (water only) or chronic inanition (underfeeding), 

 with loss of 34-36 per cent in body weight, Jackson ('15) found the corre- 

 sponding average loss in the weight of the hypophysis was about 26 per cent. 

 In young albino rats held at constant body weight by underfeeding from 3 to 10 

 weeks of age, the hypophysis increased 18 or 19 per cent in weight (Jackson 

 '15a). Stewart ('18, '18a) found a somewhat greater increase (24-33 P er cent) 

 in most cases when the underfeeding began at birth, unless the inanition was 

 prolonged beyond 10 weeks of age, with irregular results. 



Stewart ('16) noted practically normal weight of the hypophysis in albino 

 rats refed for 1-4 weeks after underfeeding from 3 to 12 weeks of age. The 

 hypophysis likewise appeared nearly normal in weight in albino rats underfed 

 from birth to 3, 6 or 10 weeks, and then refed to 25, 50 or 75 g. in body 

 weight (Jackson and Stewart '19) (Table 7). In other series of rats, under- 

 fed from birth to 3 or 10 weeks, or from 3 to 20 weeks or 1 year, and then refed 

 to maximum (adult) size, Jackson and Stewart ('20) found the hypophysis 

 variable in weight, and slightly subnormal in most groups (Table 8). 



Observations on the pineal body by Stewart ('18) indicated no appreciable 

 change in weight in young albino rats underfed for various periods. The 

 pineal body was found 6-25 per cent subnormal in weight by Jackson and 

 Stewart ('19) in refed rats, possibly indicating that early inanition (especially 

 when prolonged) may tend to inhibit the later growth of this organ. But in 

 another series, Jackson and Stewart ('20) found the weight of the pineal body 

 in the refed rats more irregular, so no definite conclusions can be drawn. 



A more detailed volumetric and histological study of the hypophysis in 

 young and adult albino rats during inanition was made by Jackson ('17), with 

 the following results: 



" During inanition, the volume-changes in the lobes are variable. In young 

 rats held at maintenance (constant body weight), the pars anterior is somewhat 

 reduced, the intermedia and nervosa correspondingly larger. In chronic 

 (adult) inanition the partes anterior and intermedia appear reduced, the nervosa 

 increased. In acute (adult) inanition, the pars anterior appears relatively 

 increased, intermedia decreased, and nervosa unchanged in relative volume. 



"In young rats refed one-half week, one week, two weeks and four weeks 

 after maintenance, there is some variability, but in general a gradual return to 

 the normal proportions in the lobes of the hypophysis. After a prolonged period 

 of maintenance, however, the relative volume of the lobes may remain perma- 

 nently abnormal. 



"In the pars anterior of the normal newborn rat, the vessels and associated 

 stroma form 6.7 per cent by volume, increasing to 9.6 per cent at three weeks, and 



