126 EFFECTS OF INANITION IN THE PKEGNANT ALBINO RAT. 



The visceral group as a whole is subnormal in weight during prenatal inanition. 

 In postnatal inanition, however, it shows a marked tendency to gain in weight in the 

 younger rats (underfed from birth to an average of 16 days, and from birth to 10 

 weeks, Stewart, 1918a, 1918). When the underfeeding is begun at 3 weeks of age, 

 the visceral group shows a slight gain or just maintains a growth equal to that of the 

 controls. In cases of prolonged underfeeding in the young rats (under 1 year of age) 

 and in adult life, the visceral group shows a decided loss. It should be noted, as 

 before mentioned, that the gain or loss in the visceral group during inanition is 

 dominated by a loss or gain in weight of the certain large organs, such as the liver, 

 lungs, gastro-intestinal tract, and brain. In postnatal inanition the gain in the vis- 

 ceral group compensates for the loss in the "remainder," while in prenatal inanition 

 the converse is true. Thus it is evident that the strongest growth tendency mani- 

 fested by the visceral group during inanition is at a period just after birth and that 

 it becomes progressively weaker thereafter. 



The musculature has a subnormal weight in prenatal inanition and shows but a 

 slight gain (musculature and skeleton combined) in rats underfed from birth to an 

 average of 16 days of age (Stewart, 1918a). It is in rats underfed from birth to 3 

 weeks of age that the musculature manifests its greatest gain. This tendency to 

 gain is present, but weaker, in rats underfed for longer periods (Jackson, 1915a; 

 Stewart, 1918). In both acute and chronic inanition in adult rats the musculature 

 loses in about the same proportion as the body as a whole (Jackson, 1915). It is 

 evident, therefore, that the growth tendency in the musculature during inanition 

 in the rat is weakest before birth, slightly stronger just after birth, and strongest at 

 a period between birth and 3 weeks of age, declining thereafter. 



The skeleton has a subnormal weight during prenatal inanition and shows a 

 very slight gain in rats starved from birth to an average of 16 days. In young rats 

 underfed for longer periods, up to adult life, the skeleton shows a marked tendency 

 to gain. During inanition in adult rats the skeleton shows very little change in 

 weight. Thus the growth tendency manifested by the skeleton during inanition is 

 weakest before birth and slightly stronger from birth to 16 days of age. At 3 weeks 

 of age, however, it is quite strong, increasing slightly toward adult life. It thus 

 appears that the growth tendency manifested during inanition develops at a rela- 

 tively later period in the skeleton then in the musculature, but persists longer in 



the former. 



The integument manifests a moderately strong growth tendency during pre- 

 natal inanition and just after birth (in rats underfed to an average of 16 days of 

 age) . In rats underfed from birth to 3 weeks of age the integument shows no gain, 

 and inrats starved for longer periods it shows a constant loss in weight. 



In postnatal inanition the organs as a general rule manifest their strongest 

 growth tendency in the youngest rats (underfed from birth to an average of 16 days 

 (Stewart, 1918a). The liver, suprarenals and ovaries are exceptions to this rule. 

 The liver loses markedly at this period as compared'with a gain at later periods. 

 The suprarenals and ovaries show a very slight gain as compared with marked gain 

 in later periods. 



