196 THE FCETUS. 



towards the median line; their edges, which are somewhat inclined 

 towards each other, look chiefly in a forward direction. 



497. From the thirtieth to the fortieth day the fore-arm and the leg 

 are visible, and the points of the fingers begin to emerge. At forly- 

 five or fifty days the elbow and arm begin to detach themselves from 

 the breast to which they had been before attached by means of a mem- 

 brane. The heel and knee also become evident; nevertheless, the 

 thigh appears very short, as well as the arm, which doubtless depends 

 upon its notbeing as yet completely detached from the sides of the ab- 

 domen. All the fingers are very distinct, and the gelatinous substance 

 which unites their base no longer extends as far as their ends, the 

 foot ceases to resemble the hand; the toes are arranged difl"erenlly 

 from the fingers; in one word, these two organs exhibit nearly the 

 same characteristic appearances they are to have at birth. It is 

 manifest that one is designed for the purpose of standing, and the 

 other to be used for the prehension of objects. This peculiarity alone 

 might serve completely to expose the absurdity of those sophists who 

 have insisted that the primitive mode of walking, in man, was simi- 

 lar to that of brutes. 



498. Coccyx and genitals. From the foregoing it will have been 

 seen, that during the three first weeks the trunk terminates by a ver- 

 miform extremity, and this sort of sacro-coccygeal tail, which is bent 

 very much forward, becomes straighter as its cavity becomes more 

 filled up. I ought here to remark, that its edges soon become con- 

 tinuous with the abdominal mass, or are concealed by the roots of 

 the pelvic extremities. The space between it, the insertion of the 

 umbilical cord and the feet, the extent of which, until the fifth or 

 sixth week, scarcely exceeds a line or a line and a half, retains for a 

 considerable time the appearance of an excavation; it is subsequent- 

 ly filled by the gradual growth of the genito-urinary organs; and the 

 development or concentric increase of the abdominal parietes and 

 sides of the coccyx and sacrum at last complete it. 



499. Towards the fortieth or forty-fifth day a black point is dis- 

 tinguishable in front of the coccyx, and indicates the situation of the 

 anus; a little more tow-ards the umbilicus may be seen a conical tu- 

 bercle, with a groove on its inferior part, constituting the rudiment 

 of the clitoris, or penis, according to ihe sex of the foptus. A slit 

 which is of sometimes greater and sometimes less breadth and depth 

 extends from one of these points to the other. In several instances, 

 however, I have thought that the intervening space in well formed 

 embryos was smooth; so that, up to its period, there is nothing to 

 point out the difference between the sexes: we are tempted to sup- 

 pose that every fcRtus belongs to the male sex, for there are in 



