116 EFFECTS OF INANITION IN THE PREGNANT ALBINO RAT. 



tion experiments (table 6). Stewart (1918a) found a slight gain (3 per cent) in the 

 lungs of rots underfed from birth to an average of 16 days. On underfeeding from 

 birth to 3 weeks, and from birth to 10 weeks of age, the lungs showed a loss of 26 per 

 cent in both series (Stewart, 1918). Jackson (1915a) found that the lungs lose 15 

 per cent in rats starved from the age of 3 weeks to 10 weeks. He also found a 

 loss of 13 per cent in the lungs in a group underfed between the ages ol 10 weeks and 

 8 months. Stewart (1918), however, found the lungs in rats underfed from an age 

 of 3 weeks to 1 year to gain in weight 28 per cent (probably pathological). Jackson 

 (1915) found that the lungs show a tendency to lose weight in adult rats in both 

 acute and chronic inanition and that this loss of weight is about in proportion to the 

 loss of the body as a whole. Consequently, it may be concluded that the lungs 

 exhibit a very weak growth tendency during prenatal as well as during postnatal 

 conditions of inanition. 



Liver. — The Wistar norm (Donaldson, 1915) for the liver of the newborn rat is 

 0.205 gram, with a body-weight of 4.9 grams. Stewart (1918a) gives the weight as 

 0.245 gram or 4.9 per cent of the body-weight, 5.03 grams. Jackson (1913) finds a 

 weight of 0.230 gram or 4.3 per cent of the body weight. In my newborns the 

 weight of the liver is 0.250 gram or 5.1 per cent of the body-weight, 4.92 grams. 



In my prenatal controls the liver forms 9.1, 8.7, 7.8, 8.1, and 7.7 per cent of the 

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

 relative weight of the liver in the prenatal controls markedly exceeds that of the 

 normal newborn rat. This difference in relative weight decreases, however, as the 

 normal birth-weight is approached. 



In my test rats the liver forms 4.1, 4.5, 4.6, 4.9, and 4.4 per cent of the body- 

 weight in Groups I to V, respectively (computed from table 5) . In the smaller test 

 rats, the liver forms a relatively smaller percentage of the body-weight than in the 

 normal newborns. In the prenantal controls, however, the liver forms a much 

 higher relative percentage of the body-weight than in either the normal newborns 

 or in the test rats. 



In the test rats the absolute weight of the liver is markedly subnormal in all the 

 groups (table 5), averaging 45 per cent below that of the prenatal controls. In the 

 range of the individual weights in the same groups the highest weight for the liver 

 in the test rats is much below the lowest weight in the prenatal control. Thus in 

 prenatal inanition the growth ot the liver is markedly retarded, reaching an absolute 

 weight of approximately one-half that of the prenatal controls. 



In postnatal inanition, Stewart (1918a) found that the liver loses 23 per cent 

 in rats held at a constant weight from birth to an average of 16 days (table 6). In 

 two other groups underfed from birth to 3 weeks, and from birth to 10 weeks, he 

 found that the liver gains in weight 17 and 64 per cent, respectively. Jackson 

 ( 1915a), in young rats underfed from the age of 3 weeks to 10 weeks, found a gain of 

 10 per cent in the liver-weight. In rats starved for a longer period, or where it was 

 begun later, the liver shows a loss of weight (Jackson, 1915a; Stewart, 1918). 

 Jackson (1915) found that the liver loses markedly in cases of acute and chronic 

 inanition in adult rats. 



