110 EFFECTS OF INANITION IN THE PREGNANT ALBINO RAT. 



In general, no attempt was made to remove any of the fat, such as the "nuchal 

 fat pad," retroperitoneal fat, etc., all of which was included in the musculature. 



In my normal newborns (body-weight 4.92 grams) the average weight of the 

 remainder was 1.05 grams (21 per cent of body-weight); Stewart (1918a) found its 

 weight to be 1 .52 grams (30 per cent of net body-weight, 5.03 grams) . This weight 

 is considerably higher than mine, probably due to the fact that he included more fat 

 with the remainder than with the musculature. Jackson and Lowrey (1912) , how- 

 ever, found its weight to be 0.97 gram (20.56 per cent of body-weight, 5.3 grams), a 

 value very close to mine. 



In my prenatal controls the weight of the remainder forms 31, 27, 28, 23, and 23 

 per cent of the body- weight in Groups I to V, respectively (computed from table 5). 

 Thus the relative weight of the remainder in the smaller prenatal control rats 

 (fetuses) markedly exceeds that of the normal newborn rat, the difference decreasing 

 as the normal birth-weight is approached. 



In my test rats the weight of the remainder forms 37, 34, 31, 28, and 30 per cent 

 of the body-weight in Groups I to V, respectively (computed from table 5) . There- 

 fore the relative weight of the remainder in the test rats exceeds that of the prenatal 

 controls in all the groups. 



The absolute weight of the remainder in my test rats was considerably above 

 that of my prenatal controls in all the groups, the average being 25.4 per cent above 



(see table 5) . 



This relative and absolute increase in the remainder is directly opposed to the 

 results obtained in investigations on postnatal starvation (see table 6) . In rats held 

 at a constant weight from birth to 16 days, in another group underfed from birth to 3 

 weeks (body-weight 10 grams), and in another series underfed from birth to 10 

 weeks, Stewart (1918a, 1918) found in the remainder a decrease of 59, 40, and 23 

 per cent, respectively, as compared with normal controls of the same body- weight. 

 In rats underfed from the age of 3 to 10 weeks, however, Jackson (1915a) found but 

 2 per cent decrease in the remainder. In young rats underfed up to 1 year of age 

 he found a decrease of but 5 per cent, while in Stewart's series (1918) there is a 

 decrease of 33 per cent. In acute and chronic inanition in adult rats there is a 

 definite decrease in the weight of the remainder, probably due to a loss of fat 



(Jackson, 1915). 



Why the remainder should decrease during postnatal starvation and increase 

 during prenatal inanition is difficult to explain. Possibly there is a larger amount 

 df circulating fluids (blood, lymph, etc.) in my test rats than in the prenatal controls. 

 This increase in the remainder evidently compensates for the loss in weight of the 

 visceral group. This is the converse of what occurs in postnatal starvation, as found 

 1 y Stewart (1918a) in the rats held at birth-weight. 



Brain. — In my normal newborns the average weight of the brain is 0.235 gram 

 (4.8 per cent of the body-weight, 4.92 grams) . Stewart (1918a) gives the weight of 

 the brain in the newborn as 0.224 gram (4.5 per cent of the body-weight, 5.03 grams). 

 Jackson (1913) found the weight of the brain in the newborn rat to be 4.8 per cent 

 of the gross body-weight. 



