PRESENTATION OF THE FACE. 311 



hseref, per illam ita transmovetur, utfrons sensim inincurvaturam 

 ossis sacri vergat. Utque fades aperturse infra appropinquat, 

 mentwn propemodo admittitiir sub pube, simul atquefrons cum ver- 

 tice sKpra perinfeiwi protruditur. £n facialis omnis partus exor- 

 dium, progressus dc finis! 



M. Chevreul expresses himself in nearly the same manner: " I 

 can enumerate eighteen labors, says he, that occurred since 1792, 

 either in my private practice, or at the Maternite at Angers; where 

 the children presented the face, and ivhich terminated naturally. Ml 

 these children were of the common size; fifteen of them were born 

 alive; three were dead, but appeared to have been so previously to 

 the commencement of labor." 



However, a distinguished professor, M. Capuron, has recently 

 come out with great vigor in opposition to this doctrine, endeavor- 

 ing to demonstrate upon geometrical principles, that delivery by the 

 face, according to the mechanism pointed out by Boer, is generally 

 impossible, provided the woman does not receive any artificial aid. 

 But no geometry can hold good in this case; as numerous facts 

 exist, they are evidently possible. I have myself seen seven cases 

 of face presentation; the children were born alive and well; I trusted 

 the cases to nature, and no particular difficulties were observable. 



This kind of labor, therefore, is not only possible, but also for 

 the most part quite easy. M. Capuron and many others have thought 

 otherwise, because they did not perfectly understand its mechanism, 

 and were misled by the idea that the breast in such cases must ne- 

 cessarily pass the strait at the same time with the head, which is 

 wholly incorrect. It is clear, when the head presents at the superior 

 strait, with the chin towards the pubis and the forehead towards the 

 sacrum, that the fronto-mental diameter, which is only three inches, 

 or if prolonged to the anterior fontanel, three inches and a half, is 

 parallel with the sacro-pubic diameter, equal to four inches and a 

 half, and that it occupies the situation that belongs, in vertex pre- 

 sentations, to one of the diameters of the occipito-bregmatic circum- 

 ference. So far there is no disadvantage in a face presentation. 

 But at a later period, when the head descends, the chin gets below 

 the pubis before the occiput reaches the excavation, and the breast 

 is still at the superior strait while the face is actually engaging in 

 the inferior pelvic circle; then, the front of the neck, being stopped 

 by the lower edge of the symphysis pubis, compels the vertebral 

 column to react upon the posterior part of the head, which it urges 

 from behind forwards, so as to force it through the vulva, by pre- 

 senting to that opening a series of circles, whose principal chords are 

 measured by the vertical diameter of the head. The laws of me- 



