PRESENTATION OF THE VERTEX. 293 



cervix uteri. The posterior half of the head is much more weighty 

 than the anterior half. The weight of the hinder part of the trunk, 

 during the intra-uterine life, is much greater than that of the an- 

 terior portion. When the woman is standing up, sitting down, or 

 kneeling, and even when lying on her side, the anterior wall of the 

 womb is much more inclined towards the cervix than its posterior 

 wall; the back of the fnetus wdl therefore more frequently be found 

 turned towards the front of the motlier than towards her back. In 

 quadrupeds, the young are oflen found to have their bellies down- 

 wards, and almost always come head foremost, although the womb 

 is lower than the vulva; but it is to be observed that the abdomen 

 in these species weighs most, and the head least. Another no less 

 powerful cause of the frequency of this position is found in the pro- 

 portional dimensions and inclinations of the head and pelvis; the 

 abdominal strait being much larger in front than behind, and strongly 

 inclined towards the pubis, it is quite natural that the occiput should 

 commonly assume this direction, &c. The cause which so often 

 directs the occiput towards the anterior semi-circle of the strait, is 

 therefore not more difficult to understand, than that which occasions 

 the head to descend first; hence physicians were wrong to abandon 

 their researches in relation to it. 



A. First Variety. 

 Left occipilo-acetabular position. 

 1st position of Baudelocque, Maygrier, Mesdames Boivin snd Lachapelle; 

 15,809, in 22,343, Madame Lachapelle; J 5,693 in 20,517, Madame Boivin; 36 

 in 67, Lovati. 



In this position the back of the fcetus looks towards the front and 

 left; its abdomen towards the back and right. The occiput is placed 

 behind the corresponding ileo-pectineal eminence much more fre- 

 quently than behind the acetabulum, and the top of the forehead or 

 the anterior fontanel, rather than the forehead properly so called, 

 looks towards the right sacro-iliac symphysis; the right side is to 

 the right and in front, and the opposite one is behind and towards 

 the left. Its great frequency seems to depend upon the rectum be- 

 ing in pregnancy commonly filled with faeces, which forces the fore- 

 head to incline towards the right side; such at least is the opinion 

 of accoucheurs in the present day: an opinion which, besides, seems 

 to be sustained by. direct observation, since M. Duges has seen the 

 foetus in Baudelocque's second position in two women who had 

 the rectum on the right side: but this point is worthy of new re- 

 searches. 



26* 



