338 OF THE GROWTH, &c. 



the others. If the child is prefTed with faeces, 

 why does it not evacuate them in the hqour 

 amnii ? But this never happens. It appears, on 

 the contrary, that the neceffity of evacuating 

 the meconium is not fek till after birth, when 

 the motion of the diaphragm, occafioned by 

 refpiration, compreffes the inteftines, and gives 

 rife to this evacuation ; ei'pecially fince no me- 

 conium was found in the amnios of a foetus of 

 ten months, who had not refpired, and fince 

 an infant of fix or feven months difcharges the 

 meconium foon after refpiration. 



Other anatomifts, and particularly Fabricius 

 ab Aquapendente, imagined that the foetus left 

 the uterus, from a defne of being refrefhed by 

 refpiration. But this caule feems to be as chi- 

 merical as any that has been mentioned. It is 

 impoflible that a foetus can have any idea of re- 

 fpiration ; and far lefs can it have any concep- 

 tion whether refpiration v;ould be agreeable or 

 difagreeable. 



After confiderlng all thefe hypothefes, I fu- 

 fped that the delivery of the foetus depends on 

 a caufe of a very different nature. The men- 

 ftrual flux returns at ftated intervals. Though 

 its appearance be interrupted by impregnation, 

 its caufe is not defiroyed ; and, though no blood 

 is exhibited at the accullomed period, yet a re- 

 volution in the fyftem, fimilar to what happens 

 before impregnation, muil take place. It is for 



this 



