BUT besides this _Doctrine_, I conceive there are _Four_ very considerable _natural Causes_ that may be reasonably assign’d for it; _viz._
I. THE _DEBILITY_ of _Human Nature_, which in Time of _Labour_ requires sometimes the whole _Strength_ of the WOMAN, and sometimes that of the _INFANT_ too; and that commonly above what _Either_ can well afford.
II. THE dull _Sedentary Life_ which _Women_ generally lead and indulge themselves in; as appears plain from what I have often observed in _Germany_ and _Holland_: For the _Women_ of those _Countries_ generally accustoming themselves to some sort of active _Labour_ and industrious _Exercise_, have much easier _BIRTHS_ than any _Others_ that I know.
III. BUT one general and universal _Reason_ of it is, that the _Bone_ call’d OS COCCYGIS, which is loosely join’d to the inferiour Extremity of the _Bone_ call’d SACRUM, bending outwards during the Time of LABOUR; as the _CHILD_ advances, its _Head_ presseth the _Gut_ call’d RECTUM hard against it; which causeth most severe, acute, and extreme _PAINS_.
IV. ANOTHER principal and universal _Reason_ of it, is, the BULK of the _Head_ of the _INFANT_; which (according to _Albertus Magnus_) is equal in the time of _BIRTH_, to the rest of the _Whole Man_; causing a violent _Dilatation_ of the WOMB, that is very _strait_ in comparison of this BULK; and _That_ being a very sensible _Membranous Composition_, _This_ must (of Necessity) occasion most grievous and almost intolerable _PAINS_. Whence I come to
CHAP. XLI. _Of the CAUSES of a sooner, or later BIRTH._
MANY great Men have written and answer’d promiscuously on this _Head_, suggesting a vast Variety of _Reasons_ for it: But as _Every One_ is left to think and judge the Best he can for Himself, so I shall (in this place) only animadvert upon _Those Causes_, which I most entirely approve of; and as they are _Fivefold_, so I think, they either depend upon the _Genital Seed_; the _Formative Faculty_; the _Temperature_ of the WOMB; the _Constitution_ of the WOMAN; or the _Influence_ of _Superiour Bodies_.
I. THE _natural Cause_ may depend upon the SEED: Because as there is among GRAIN several _sorts_, some of which fructify and ripen in _Three_, some in _Four Months_, and others which require much _longer Time_; so it may be also in _human_ SEED, that it may differ as much in its Kind. Which Truth is very evident from what has been frequently observed, that _Women_ bring forth the _Children_ of different FATHERS, at different Times; whereof I shall only mention the remarkable Instance of _Vestilia_[149]: who was thus deliver’d of _Three Children_ to her _Three several Husbands_, HERDITIUS, POMPONIUS, and ORSITUS, all noble Citizens of _Rome_: _viz._ Of the _one_ in the _7th_, of the _other_ in the _11th_, and of the _last_ at the Expiration of _8 Months_.