278 LABOR-PAINS. 



especially in a first labor, communicates an impression like that 

 which would be felt upon touching a ring of fine cord slightly- 

 stretched. In the latter half of the first stage it becomes, on the 

 contrary, thicker, and sometimes forms a kind of roundish cushion, 

 which seems to yield before the child's head, but gradually disap- 

 pears when the head passes or engages in the strait. The very con" 

 trary of this is remarked in women who have had many children;^ 

 the lips of the os uteri, which at first are soft and supple, still some- 

 times retain a thickness of several lines, even although the labor 

 may be somewhat advanced; it is, however, only at a later period, 

 when the bag of waters begins to form, that they begin gradually 

 to grow thinner. 



698. In both the above cases', the diminution in thickness is far from 

 taking place with the same regularity on every point of the circum- 

 ference of the circle. I have often seen its posterior half as thin as 

 the edge of a sheet of paper, while its anterior semi-circumference 

 formed betwixt the head and pubis a cushion from three to four 

 lines in thickness. This inequality, which is in some sort natural, 

 and almost always to be met with in various degrees, ought not to 

 be overlooked, whenever we attempt to determine the duration of 

 the labor: by touching the anterior half of the cervix without car- 

 rying the finger far back, one might be led to prognosticate a pretty 

 tedious time, while another person, after having explored the opposite 

 side, would announce that the labor is just about to come to a 

 conclusion. 



699. The shape of the os uteri during the process of dilatation is 

 no less variable than the thickness of its lips. It is pretty nearly 

 circular where it corresponds to the centre of the pelvis; but more 

 commonly it is oval, with the broadest part turned backwards, or to 

 one side, right or left, according as the fundus is inclined in this or 

 that direction; sometimes elliptical, especially when the child pre- 

 sents in a transverse direction, it exhibits, in other ' cases, certain 

 inequalities which depend upon its different points not having the 

 same consistence nor the same extensibility. 



700. All those authors who have maintained that the foetus is the 

 efficient cause of delivery, have necessarily also admitted that it is 

 the cause of the dilatation of the os uteri. The common people, 

 mostly, still reason in this way, and Vigarous seems to be of the 

 same way of thinking; but since it has been ascertained that, in the 

 expulsion of the whole or part of a dead foetus, the os uteri dilates 

 just as it does for a living child, this opinion, now become superan- 

 nuated, has been completely rejected. We have, says A. Petit, one 

 decisive proof that the foetus does not dilate the orifice, in the fact, 



