112 OF TRUE PREGNANCY. 



cannot adopt such an opinion, for the same changes are observed 

 in women who continue to be subject to a periodical discharge 

 during pregnancy, and where the uterus is distended by a polypus, 

 while they are not met with in a case of simple amenorrhoea. Tra- 

 versed by larger nerves, and receiving a larger supply of vivifying 

 fluids, the uterus enjoys a livelier sensibility: in the unimpregnated 

 state it may be touched, struck, pressed upon, without, so to speak, 

 causing the woman to feel any pain; during the growth of the ovum, 

 on the contrary, the least jar, the least touch of the fostus are in- 

 stantly felt by the mother; both its sensibility and contractility are 

 of a grade almost as high as that of the organs of relation. 



284. To explain the extraordinary development of the uterine 

 caviiy, the ancients taught that the ovum dilates it by growing, just 

 as we can dilate a glass tube by blowing into it, as we distend a 

 bladder by filling it with a fluid or air, or as we can spread out a 

 ball of soft wax. Puzos has not rendered this hypothesis more sus- 

 tainable, by calling to its support the laws observed by fluids in trans- 

 uding from without to the inner side of any inert vessel; for as, in 

 physics, the force of impulsion of fluids is measured by the height 

 and thickne?s of the column, it is clear that in this case, the distend- 

 ing effort would increase in an inverse ratio to the resistance; that, 

 from being very feeble at the beginning, when the density of the 

 organ is considerable, it would at the close be doubled ten times to 

 overcome a less difficulty. Would it be any better to say, with Van 

 Helmont, that the womb dilates spontaneously under the influence 

 of a bias meteorisant, or to admit, with Levret and the moderns, that 

 like the heart and the erectile tissues, it grows actively, and by the 

 mere force of its vital properties? But in reasoning thus, the fact 

 is explained without indicating the cause. It is at least certain that 

 the dilating force, altogether foreign to the product of conception, 

 exists in the gestative organ itself: a circumstance that beyond 

 question proves this to be the case, is, that in preternatural preg- 

 nancies, as remarked by Levret, Bertrandi, Meckel, Chaussier, &c. 

 the uterine cavity, though empty, dilates as it does in an ordinary 

 gestation. 



285. To explain this dilatation, it is useless, with Malpighi, to refer 

 to a fermentative principle contained in the semen, or with Blumen- 

 bach, to a peculiar vital action; the turgescence occasioned by fe- 

 cundation, and kept up by the ovum, affords a very satisfactory rea- 

 son for it; the congestion, of which the womb is the seat, invites to 

 it an excess of nutrition; the new molecules incessantly deposited 

 there, necessarily elongate its fibres; the vascular channels are both 

 uncoiled and enlarged at the same time, and as this unfolding and 



