Prenatal Growth of the Human Body. 139 



5), the spleen is at first relatively small, but increases slowly to an 

 average of .176 per cent of the whole body in the 7th month. Abont 

 this time it appears to increase rapidly in relative size, avor,a2,in_<>- 

 over .4 per cent in the Sth and 9th months. In the full-term still- 

 born (143 cases) the spleen averaged .32 per cent of the total body 

 weight, and in the live-born (101 cases) .43 per cent. Vierordt gives 

 .;'>4 per cent of the total body weight for the spleen in the new-born, 

 and .25 per cent for the adult. The fetal spleen, as in postnatal life, 

 is subject to extreme individual variations in relative size. 



Stomach and Intestines. 



Only a few observations upon the prenatal growth of the alimentary 

 <3anal are available, chiefly (besides my own) those of Arnovljevic 

 (3) and Brandt (8). The data upon stomach and intestines (in- 

 cluding mesentery) are included in Tables IV and V. The data for 

 stomach and intestines in Tables IV and V include contents. No data 

 are available for the empty stomach before the 4th month, but since 

 the contents are usually slight at this time, the figures given for the 

 stomach plus the contents are probably only a little larger than they 

 ^vould be for stomach alone. It seems that the empty stomach is 

 relatively somewhat larger at an early period than later. It varies 

 irregularly in relative size, the average per cent of the entire body 

 in the different months varying from .16 per cent to .39 per cent. 

 A larger series would doubtless give more uniform figures. The 

 figures for stomach with contents are at first but little larger than 

 those for the empty stomach ; but in the later fetal months the contents 

 (chiefly mucous) become relatively much larger in amount. In the 

 full-term fetus the empty stomach averaged .20 per cent of the entire 

 body weight (7 cases), while the stomach plus contents formed .49 

 per cent (8 cases). 



The intestine is relatively small in the early embryo, not being at 

 the 5th week very much larger than the stomach. It grows very 

 rapidly, however, so that in the full-term fetus the weight of the in- 

 testines (either filled or empty) averages more than six times that of 

 the stomach. As in the case of the stomach, the contents of the in- 



