128 EFFECTS OF INANITION IN THE PREGNANT ALBINO RAT. 



swellings in the uterine horns revealed a mass of degenerating tissue, with no 

 evidence of any fetal structures. 



(3) The length of gestation in the mothers starved during the last half of preg- 

 nancy varied from 21 to 26 days. Eight (of the 22 total) were above the 23-day 

 normal limit, 6 with a gestation-period of 24 days, 1 of 25, and 1 of 26. The average 

 p eriod of gestation was 23 days, or 1 day above the normal average. 



(4) No abortions or premature deliveries were observed in any of the underfed 



rats. 



(5) Of a total of 120 newborn from mothers starved during the last half of 

 pregnancy, 41 were found dead after delivery. Whether these were dead in utero, or 

 died during delivery or afterwards, is uncertain, since at birth they dropped through 

 the wire bottom of the cage. Those living-born that were inclosed within the 

 amniotic sac died of suffocation. Those found living seemed quite vigorous. 



(6) The average number of observed young per litter, from mothers starved 

 during the last half of pregnancy, was 5.9. (The normal average number of young 

 per litter was 7.0 in 1,089 litters; King and Stotsenburg, 1915.) 



(7) A condition of relative sterility apparently results in females starved 

 during the last half of pregnancy. Of the total number starved but 4 became preg- 

 nant a second time. 



(8) The average weight of the newborn from mothers starved severely during 

 the last half of pregnancy was approximately 3 grams, or 40 per cent below the 

 normal birth-weight of 5 grams. 



(9) There was no constant relation between the percentage loss in weight of the 

 mother and the weight of the newborn. In general, however, the largest females 

 showed the largest relative loss in weight and bore the largest young; and the weight 

 of the newborn tends to be inversely proportioned to the severity of the starvation. 



(10) A prenatal norm for the various systems and organs was established by 

 comparing the relative weights, at the various fetal stages, with those of the normal 

 newborn. 



(11) During prenatal inanition the tail grows in length faster than the remainder 

 of the body, thus giving rise to relatively long-tailed individuals. 



(12) Concerning the changes in the general body proportions during prenatal 

 inanition, the head and limbs are slightly above normal weight, counterbalanced by 

 a lower weight in the trunk. 



(13) The observations on the various systems are summarized as follows: The 

 "remainder" has a weight 25 per cent higher in the test rats than in the prenatal 

 controls. The integument shows a weight averaging 10 per cent above normal in 

 the test rats. The musculature and moist skeleton are slightly subnormal in weight 

 in the test rats, being 5 and 7 per cent, respectively below the prenatal norm. 

 However, the dried skeleton in the test rats has a weight 12 per cent above the pre- 

 natal norm. The visceral group, as a whole, has a markedly subnormal weight in 

 the test rats, being 18 per cent below the prenatal norm. This is due chiefly to the 

 subnormal weight of the liver and lungs. The low weight in the visceral group 

 evidently compensates for the high weight of the "remainder." 



