112 EFFECTS OF INANITION IN THE PREGNANT ALBINO RAT. 



Stewart (1918a), in starvation 17 to 22 days after birth, found the absolute weight 

 of the brain to gain 125 per cent above that of the controls of the same body-weight. 

 It must be remarked, however, that in my tests the exact character and extent of the 

 inanition of the fetus are somewhat uncertain. 



Spinal cord. — In my normal newborns the spinal cord weighs 0.036 gram 

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

 of the spinal cord in the newborn as 0.035 gram (0.70 per cent ot the body-weight, 

 5.0 grams) . The Wistar norm (Donaldson, 1915) for the spinal-cord weight is 0.034 

 gram at body-weight of 4.95 grams. 



The weight of the spinal cord in my prenatal controls forms 1.12, 1.00, 0.91, 

 0.83, and 0.75 per cent of the body-weight in Groups I to V, respectively (computed 

 from table 5). Thus it is evident that the spinal cord, similar to the brain, in the 

 prenatal controls has a higher relative weight than in the normal newborn rat. 



In my test rats the weight of the spinal cord forms 1.13, 1.01, 0.86, 0.80, and 

 0.75 per cent of the body-weight in Groups I to V, respectively (computed from 



table 5). 



Thus, in the smaller rats, both the test rats and prenatal controls, as com- 

 pared to the normal newborns, the spinal cord torms a relatively higher percentage 

 of the body-weight, this tendency lessening with the increase in size of the rats, 

 until in the larger rats this difference in relative weight disappears. 



From the data in table 5, the absolute weight of the spinal cord is lower in the 

 test rats than in the prenatal controls, with the exception of Groups I and II, 

 where it is respectively 6 and 2 per cent higher in the test rats. The absolute 

 weight in all the groups averages but 0.26 per cent higher in the prenatal controls 

 than in the test rats. This is such a slight difference that it might very well be 

 attributed to errors in technique, since it is very difficult to remove the cord intact 

 from these small rats and also to sever the head from the trunk at exactly the same 

 place. Probably there is very little change in the spinal cord of the fetus during 

 inanition in the mother. The fact that the body-length in the tests and controls 

 varies but little (1 per cent higher in the test rats) would lead one to expect but 

 little difference in the corresponding weights of the spinal cord. 



The results obtained in postnatal inanition, however, might lead one to expect 

 an increase in the size of the cord in the stunted individual. Bechterew (1895), in 

 acute inanition of puppies and kittens, made a study of the central nervous system 

 after death of the animal and found the least loss in the spinal cord. Donaldson 

 (1911) found a slight increase in the weight of the spinal cord in young rats, held at 

 body-weight of 34 grams from 30 to 51 days of age. Jackson (1915) found no change 

 in the weight of the spinal cord in acute inanition in adult rats, while in chronic 

 inanition in adult rats he found a slight decrease in the weight. 



In newborn rats, however, Stewart (1918a) noted a marked tendency tor the 

 cord to continue growing during inanition in which the body is kept at nearly 

 constant weight. From the data in table 6, it is evident in underfed young rats that 

 the spinal cord possesses a very strong growth tendency, greatest at or shortly 



