THE LAWS OP GROWTH IN MAN. 493 



spine. Tlie fore ai-m is about as long as the upper arm, 

 and the leg as the thigh. The manus and pes are very- 

 similar in size and form ; and neither pollex, nor hallux, are 

 so different from the other digits as at later periods. In a 

 fcetiis rather more than five inches high, the head occupies 

 a fourth of the entire height ; the arms are longer than the 

 spine by one- sixth of their whole length, and are a little 

 longer than the legs. The fore arm is about as long as the 

 upper arm, and the thigh is a little longer than the leg. 

 The manus and pes are about equal in length. In a foetus 

 eight and a half inches high, the head measures less than a 

 fourth of the whole height ; the anns are longer than the 

 spine by a fourth of their whole length, and they are longer 

 than the legs. The extremities of the digits reach down 

 to the knee when the body is erect. 



At full term, the height of the head of the human fcetus 

 is rather less than a fourth that of the whole body, and the 

 legs are longer than the arms. The arm is longer than the 

 fore arm, and the thigh than the leg. The hands and 

 the feet are still about equal in length. 



Thus it wotdd appear that, while the head gi'ows more 

 slowly than the rest of the body, throughout the period of 

 gestation, after the embryo has attained more than two 

 inches in length; the arms grow proportionally quicker 

 than the body and legs, in the middle of gestation, when 

 the proportions most nearly resemble those of the Anthro- 

 pomoi-pha. In the latter part of the period of gestation the 

 legs gain on the arms, and the proximal segments of the 

 limbs on the distal ones. After birth these changes are con- 

 tinued. The adult has, on the average, three and a half 

 times the height of the new-born child, and his arms are 

 elongated in the same proportion. But the head is only 

 twice as large, while the legs of the adult are five times as 

 long as those of the child. At all ages after birth, the 

 distance between the extremities of the digits of the out- 

 stretched arms is equal to the height in average Europeans. 



Sextial differences, independent of the genitalia, are per- 

 ceptible at bii-th ; and the female infant is, as a rule, slightly 



