SPONTANEOUS EVOLUTION. 423 



which Denman has mentioned under the title of spontaneotis evolu- 

 tion, and which M. Murat calls spontaneous version, have been care- 

 fully observed by Madame Lachapelle, and noticed by Garthshore, 

 Martineau, &c. Neither were the ancients wholly unaware of them, 

 since they advise that, for the purpose of bringing the head back to 

 the strait, the woman should be shook or assume certain positions. 

 Most modern authors have also remarked them, since they have laid 

 it down as an established rule, that the position of the child, while 

 still enclosed in the membranes, is so variable, that, in order to fix it, 

 it becomes necessary to rupture the ovum, choosing a moment when 

 the head corresponds to tlie centre of the pelvis; but upon this, as 

 upon all those phenomena that have not been the objects of special 

 study and attention, little thought has been given to the practical con- 

 sequences that might follow it. 



961. Allhougli the spontaneous evolution takes place most fre- 

 quently where there is a superabundant quantity of liquor amnii, 

 where the foetus is not large, where the womb is very much inclined, 

 or where the pelvis is badly formed, it may, nevertheless, be some- 

 times observed in the directly contrary conditions. Although it 

 more commonly and easily takes place before the rupture of the 

 membranes, it is, notwithstanding, found to occur after the evacua- 

 tion of the waters: a young woman, in her second pregnancy, was 

 admitted into the hospital of the Ecole de INIedecine, at ten A. M. 

 in the month of August, 1825. The os uteri was then but little 

 dilated ; nevertheless, I discovered that the shoulder presented in 

 the second position. The waters were not discharged until three 

 o'clock in the afternoon; four students, who were aheady well ad- 

 vanced, touched and recognised tlie presence of the shoulder, as I 

 had done. I did not wish to bring down the feet; the pains were 

 neither very strong nor very frequent, and I had some confidence in 

 the assertions of Denman. At eight o'clock the shoulder was found 

 to be evidently moved towards the left iliac fossa, and I could easily 

 feel the ear to the right. At eleven o'clock the temple was nearly in 

 the centre of the orifice: the energy of the contractions was greater, 

 and the os uteri completely effaced. At midnight the occiput came 

 down, and in the space of an hour the child was expelled in the right 

 occipilo-acetabidar position. 



962. It appears to me that the explanation of spontaneous evolu- 

 tion is an easy matter: the head of the foetus, which is its most 

 solid, voluminous, and regularly rounded part, and on that account 

 its most slippery portion, naturally tends towards one of the two ex- 

 tremities of the great diameter of the uterus, and towards the cavity 

 of the pelvis; if, under the influence of any cause, it has assumed 



