Prenatal Growth of tlie Human Body. 



14a 



while to mention briefly the data available, which are presented in the 

 following table : — 



Body Weight. 



Skeleton and 

 ligaments.... 



Musculature. 

 Skin 



Subcutaneous 

 fat , 



Average 



Adult 

 (Vierordt) • 



66200 g. 



17.48 % 

 43.4 % 



17.77 % 



It therefore appears that in the fetus the skeleton forms a some- 

 what larger percentage of the total body weight than later. The 

 musculature, on the other hand, increases in relative amount with age. 

 The skin also increases, on account of the accumulation of subcutane- 

 ous fat. In the adult, the skin, exclusive of subcutaneous tissue, 

 forms only about 6 per cent of the entire body w^eight (average of 6 

 normal adults, by Welcker and Brandt). 



Variations According to Sex. 



In Table VI, the relative size of several organs in the various 

 months, grouped according to sex, is shown. The columns "No." 

 give the number of cases (including my own and those already 

 recorded in the literature), while "per cent" indicates the percentage 

 of the entire body (chiefly w^eight, except in my own cases). The 

 average w^eight of the entire body in each group is given at the foot 

 of each "per cent" column. 



It will be noted that the average weight of the entire body is larger 

 for the male in each month, excepting the 5th and 9th months. In 

 the 9th month, the number of cases (5) is too small to be significant, 

 and the figures for the 5th month may be accidental. The conclusion 

 is therefore evident that the male fetus is heavier than the female 

 fetus of corresponding age throughout the fetal period. We know, 

 of course, that this is true in the newborn. The conclusion that it 

 is true for the entire fetal period is strengthened when it is remem- 



