EFFECTS OF INANITION IN THE PREGNANT ALBINO RAT. 115 



In my test rats the weight of the heart forms 0.55, 0.53, 0.54, 0.53, and 0.49 

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

 Thus the relative weight of the heart in the test rats is slightly higher than in the 

 prenatal controls. The relative weight in both the test rats and prenatal controls 

 is less than that in the normal newborn rats. It is also evident that in both the pre- 

 natal controls and test rats the relative weight of the heart is greater in the smaller 

 as compared with the larger rats. 



The absolute weight of the heart is constantly higher in the test rats than in 

 the prenatal controls, the difference being most marked in Group I (table 5) in 

 which the heart weight in the test is 17 per cent higher than that in the prenatal 

 controls. This difference, however, is not so pronounced in the other groups, 

 averaging for all groups 8 per cent above in the test rats. 



This gain in heart-weight in prenatal starvation agrees with the results of 

 Stewart (1918a), who noted a gain of 26 per cent in absolute weight of the heart 

 in test rats kept at a birth-weight of about 5 grams for an average ol 16 days. How- 

 ever, in another series (Stewart, 1918) starved from birth to 3 weeks (body-weight 

 10 grams), the heart showed a loss of 5 per cent. In still another group, underfed 

 from birth to 10 weeks (body-weight 24 grams), Stewart (1918) found a gain of 27 

 per cent in the weight of the heart. In slightly older rats, underfed for various 

 periods, the heart loses slightly (Jackson, 1915a; Stewart, 1918), while in adult 

 rats the heart shows a decided loss in both acute and chronic inanition (Jackson, 

 1915). 



Lungs. — Jackson (1913) gives the absolute weight of the lungs as 0.078 gram or 

 1.6 per cent of the body-weight, 5.1 grams. The Wistar norm (Donaldson, 1915) is 

 0.079 gram, or 1.6 per cent of the body-weight, 4.9 grams. In my newborn controls 

 the weight of the lungs is 0.073 gram, or 1.5 per cent of the body- weight) , 4.92 grams. 



In my prenatal controls the lungs form 2.8, 2.7, 2.3, 2.0, and 2.1 per cent of the 

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

 relative weight of the lungs is markedly higher in the prenatal controls than in the 

 normal newborn rats. This difference in relative weight is greatest in the smaller 

 rats and decreases as the birth-weight is approached. 



In my test rats the lungs form 1.2, 1.5, 1.4, 1.5, and 1.3 per cent of the body- 

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

 rats the lungs have a relative weight which is about that of the normal newborn rat, 

 whereas in the prenatal controls the relative weight is approximately double that at 

 birth. 



The absolute weight of the lungs in the test rats is 54, 44, 40, 23, and 36 per cent 

 below that of the prenatal controls in Groups I to V, respectively, averaging 39.4 

 below for all groups. It is interesting to note that in the range of the individual 

 weights the largest lungs in the test rats about equal in size the smallest in the con- 

 trols. 



This lack of ability of the lungs to grow, manifested by a subnormal weight 

 during prenatal inanition, agrees with the results obtained in the postnatal starva- 



