140 C. M. Jackson. 



testine are at first small in amount, but increase gradually, amounting- 

 on the average in the full-term fetus to about tAvice the weight (or 

 volume) of the empty intestines (plus mesentery). Vierordt esti- 

 mates that the (empty) stomach and intestine together form 2.1 per 

 cent of the entire body weight in the newborn, which is considerably- 

 higher than the figmres just given (1.23 plus .20 equals 1.43 per 

 cent). Por the adult he gives 2.06 per cent. 



For the entire alimentary canal (empty), from the end of the 

 pharynx to the anus, a few data are available. Welcker and Brandt 

 (45) cite 4 observations; fetus 3 mo., 2.49 per cent of the total body 

 w^eight; 6 mo., 3.01 per cent; newborn, 3.15 per cent, and 2.45 per 

 cent. Miihlmann obtained a much higher figure for the empty canal 

 in 2 newborn, — 6.7 per cent and 7 per cent respectively. In a series 

 extending through childhood up to the adult, he found the relative 

 weight of the alimentary canal gradually diminishing to an average 

 of about 3 per cent of the total body weight in the adult. 



On account of swallowed air and accumulated gas, in addition to- 

 the fecal contents, the volume occupied by the intestines in postnatal 

 life is relatively much greater than in the full-term fetus, — on the 

 average probably twice as great. 



Kidneys and Wolffian Bodies. 



Beginning with the 2d month, the kidneys increase in relative 

 size, at the first rapidly, then more slowly, together forming an 

 average of about 1 per cent of the total body in the 7th month (Fig. 

 4, Tables IV and V). They apparently decrease slightly in relative 

 size during the 8th and 9th months, and in the full-term still-born 

 (144 cases) the average was only .82 per cent of the total body. In 

 the live-born, however, the average (101 cases) was 1.05 per cent. 

 Vierordt estimates for the kidneys in the newborn .75 per cent; and 

 for the adult, .46 per cent. 



"\^Tien the right and left kidneys are compared in size (Tables IV 

 and VI, it is evident that in the majority of cases the left kidney is 

 slightly larger than the right. As shoAATi in Table VI, this is true on 

 the average in both sexes for every month from the 2d onward, ex- 

 cept the 2d (2 cases only), 7th (female cases), and 10th (stillborn). 



