100 EFFECTS OF INANITION IN THE PREGNANT ALBINO RAT. 



from birth to 11 to 22 days, Stewart (1918a) found the absolute weight of the in- 

 tegument in the test rats to be 25 per cent above that in the controls of the same 

 body-weight. Jackson (1915) found the integument to lose weight in nearly the 

 same proportion as the whole body in acute and chronic inanition in adult rats. 



Skeleton. — As explained under the section on materials and methods, my 

 "moist" skeleton probably corresponds closely to thatreferred to by Jackson (1915a) 

 as the cartilaginous skeleton. Since the "gold dust" solution used to rid the skel- 

 eton of its ligaments and periosteum acted too strongly upon the skeleton in my very 

 small rats, causing a disintegration of the cartilages, no attempts were made to 

 obtain anything corresponding to the cartilaginous skeleton. My observations on 

 the "dried skeleton" are consequently on the dried ligamentous skeleton. Jackson 

 and Lowrey (1912) obtained a value of 0.810 gram tor the ligamentous skeleton in 

 the newborn rats, while in my normal newborn the "moist" skeleton weighs but 

 0.381 gram, 7.8 per cent of body-weight, 4.92 grams. However, this agrees very 

 well with the weight of the newborn moist skeleton of 0.377 gram or 9.0 per cent 

 body-weight— 4.92 grams— given by Conrow (1915). It must be stated, however, 

 that despite the greatest care taken in cleaning the skeletons, their range of weight 

 was very great, even in rats of equal weights (see table 5). 



In my prenatal controls, the weight of the moist skeleton forms 7.2, 7.2, 7.4, 

 7.1, and 6.7 per cent of the body-weight in Groups I to V, respectively (computed 

 from table 5) . Thus the moist skeleton in the prenatal controls has a relative 

 weight slightly below that of the normal newborn rat. 



In my test rats the weight oi the moist skeleton forms 5.0, 7.0, 7.4, 7.2, and 7.0 

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

 Thus there is very little difference in the relative weight of the moist skeleton in the 

 test rats and prenatal controls, except in Group I, where its relative weight in the 

 test rats is considerably below that of the prenatal controls. This difference is 

 probably due to errors in technique. 



By comparing the absolute weights of the moist skeleton in the test rats with 

 the prenatal controls in table 5, it will be seen that hi Group I the absolute weight 

 of the moist skeleton in the test rats is 27 per cent less than in the prenatal controls 

 of the same body-weight. Since such a marked difference can not be accounted for 

 by any change in body-length (in fact, the average body-length of the test rats is 

 7.3 per cent greater than in the prenatal controls of this group) , it must be attributed 

 to errors in technique. In the other four groups the difference in the absolute 

 weights of the moist skeleton in the test rats and prenatal controls is very slight 

 and wholly within the limits of error, considering the difficulties of technique. 

 Probably there is very little real difference between the absolute weight of the moist 

 skeleton in test rats and prenatal controls, but one can hardly reach any definite 

 conclusion. 



It should be noted, however, that in postnatal inanition the skeleton (undried) 

 shows its greatest increase in weight, 32 per cent, in rats underfed from the age of 3 

 weeks to 1 year (Stewart, 1918). In rats underfed from birth to 16 days the gain in 



