256 CAUSES OF LABOR. 



to agree that the action of the foetus has nothing to do with that. 

 Let the head, the trunk, or any separate part be left in the womb, 

 and it will be expelled, just as if the fostus were whole, and living. 

 The placenta, the membranes, the clots, the whole after-birth, a 

 mole, a fibrinous concretion, a polypus, and all kinds of bodies, 

 in short, that are met with in the womb are incapable of any spon- 

 taneous action, and yet their expulsion is effected by the same laws 

 and announced by the same phenomena as those of the most robust 

 and the healthiest fcetus. It is therefore undeniable that the foetus is 

 not the efficient cause of labor; that instead of performing a part 

 essentially active in this process, it is on the contrary completely 

 passive from the beginning to the end of it. 



650. This cause should be sought for in the organs of the mother, 

 Avhich was not done until in the last century. Galen, J. Fabricius, 

 Gelee, Harvey, Levret, &c., had, it is true, already maintained that 

 delivery is effected under the influence of the contractions of the 

 uterus, the abdominal muscles, and diaphragm; but this opinion, being 

 "vaguely expressed, did not have any effect on the theory of partu- 

 xition. Besides, Haller thought that the womb is but a secondary 

 agent, and that the abdominal muscles and diaphragm are the chief 

 agents. To A. Petit was reserved the glory of demonstrating be- 

 yond dispute, that the efficient cause of labor is essentially consti- 

 tuted by the contractions of the uterus, and partly by those of the 

 muscles of the abdomen and thorax. 



65 1 . Essential effident cause. We acquire by direct observation 

 the proof ^that the contractions of the uterus constitute the efficient 

 principle of labor. By applying the hand upon the epigastrium 

 during a pain, the womb is felt to grow hard, to shrink, to lessen 

 in size, in one word, to contract; the finger, when introduced into 

 the vagina, perceives the orifice to become stretched, to grow thin, 

 and dilate or contract according to the stage of the labor. As 

 soon as the pain ceases, nothing of this sort can be perceived; all 

 the parts become relaxed; as soon as it returns, all the phenomena of 

 contraction reappear; but it is particularly when we are compelled, 

 in performing some operation, to introduce the hand into the interior 

 of the womb, that we abandon all doubt as to the important part 

 which it performs in the expulsion of the ovum. It pretty often 

 happens here that the operator is obliged not only to suspend his 

 progress during each contraction, but he also sometimes loses for a 

 short space all sensibility, all power to act, and the hand, which is 

 benumbed, and as it were paralysed, becomes incapable of distin- 

 guishing the objects it touches. What practitioner has not had 

 occasion to see that it is not posssible, during a pain, to pass through 



