296 NATURAL EUTOCIA. 



bly pressed in an upward and lateral direction, but they do not un- 

 fold; they could sooner be torn and separated from the inner sur- 

 face of the vulva; sometimes even the skin of the upper part of 

 the thighs yield, so as to assist the pudendum and perineum in 

 forming the sort of casque, with which the head remains partially 

 covered until it escapes entirely from the pelvis; the parietal protu- 

 berances at length pass through the bi-sciatic diameter, and the head, 

 now arrested by the resistance of the soft parts only, is soon com- 

 pletely expelled. Whilst it is passing through the vulva, the pos- 

 terior end of the occipito-bregmatic diameter, continues to rest under 

 the symphysis pubis, as upon a transverse axis, and rolls from be- 

 hind forwards, as the occiput, the sagittal suture, the parietal protu- 

 berances, the anterior fontanel, the frontal bone, the orbits, the nose, 

 the mouth and chin are seen to emerge in succession. When the 

 occipito-bregmatic circumference is expelled, the anterior edge of the 

 perineum, being drawn backwards by its natural elasticity, slides 

 over the face, which affords it a plane inclined obliquely from the 

 forehead to the chin, and approaching near the coccyx goes after- 

 wards to place itself on the fore part of the neck, forcing meanwhile 

 the head to turn over upon the mons veneris. 



731. Restitution. 'I'he head, now freed from all constraint, and 

 incapable of retaining the twist which had brought it under the arch 

 of the pubis, soon recovers its natural relation to the shoulders and 

 rest of the body, which had been temporarily changed; that is to 

 say, its antero-posterior diameter again crosses the transverse diame- 

 ter of the shoulders at right angles, as it did when at the superior 

 strait. In one word, the occiput turns towards the left groin, while 

 the chin is directed towards the opposite sub-iliac space, and the 

 title of act of restitution has been given to this rotation. 



732. After a calm of a few seconds or minutes duration, the 

 shoulders descend into the excavation, and perform a pivot motion 

 upon the anterior right and posterior left inclined planes; the right 

 shoulder being directed behind the symphysis or under the pubic 

 arch, and the left on the front of the sacrum, forces the head to un- 

 dergo a similar motion, which places it entirely crosswise, the occi- 

 put being to the left and the face to the right. In this direction they 

 engage in the inferior strait. The right appears first under the pubis; 

 the child's body bends on its right side so as to accommodate itself 

 to the pelvis; the left shoulder comes down upon the perineum; the 

 vertical axis of the thorax is parallel with the axis of the perineal 

 strait; the vertical axis of the abdomen represents ihat of the superior 

 strait; they pass the vulva together, and the rest of the body, render- 

 ed very slippery by the liquor amnii and sebaceous matter, and now 



