CHAP. I. _Of Præternatural_ CONCEPTIONS. HAVING particularly defin’d the _Natural Conception_, in Chap. I. Sect. III. and hitherto treated of its various different _Consequences_, both in GESTATION, BIRTH and CHILD-BED; I come in the next place (conformable to my promise before-mentioned) to treat of the opposite and _reverse Case_, commonly call’d (by the _Authors_) a vitious or depravated CONCEPTION: Which however, I shall distinguish by the general TITLE of _præternatural_, as I have one _Set_ of BIRTHS under the same Denomination, contained in Sect. V. But—— NOW, because I judge all such CONCEPTIONS as well as BIRTHS, to be _præternatural_, which, tho’ not according to the _ordinary Institution_ of NATURE, are yet however not _repugnant_ to NATURE: And because such CONCEPTIONS, as well as the _Præternatural_ BIRTHS already defin’d, happen after many different ways and manners; I shall also reduce and divide them into _two_ CLASSES, _viz._—— FIRST, _Præternatural_ CONCEPTIONS in respect of the _Number_; to which belong all _Superfætations_, and other Numerous CONCEPTIONS; And SECONDLY, _Præternatural_ CONCEPTIONS in respect to the _Form_ or _Substance_; to which belong all _false_ CONCEPTIONS, MOLES, MONSTERS, _&c._ Of all which particularly and briefly in their due Order, and FIRST—— [Illustration] CHAP. II. _Of_ SUPERFÆTATIONS. A SUPERFÆTATION is nothing else than a _Second_ (after a _First_) CONCEPTION: Since if divers INFANTS may be _conceiv’d_ at one _Embrace_, as will evidently appear from the following _Chapter_, we may easily believe, that _two_, _three_, or _more Embraces_, may most probably have the same _Effect_: Which is sufficiently confirm’d by the Experience of _Hippocrates_[195] himself, as well as by many other most Learned _Authors_[196]. WHEREFORE I shall spend no time in reciting here any _Instances_ I have met with of this _Nature_; only I refer the _Curious_ to a very famous collected _History_ of such BIRTHS, as in the _Margin_[197]. Whence the Certainty of _Superfætation_ is not to be doubted, and much less to be disputed: And according to _Aristotle_ the same may happen, after the _Second_ or _Third Day_, from first Conception, as well as after so many _Months_[198]. But farther,—— THE _Cause_ of all _Superfætations_ is only an _Apertion_ of the _Orifice_ of the WOMB, at the Effusion of the _Virile_ SEED. Which however (according to _Avicen_) only happens to such _Women_, as have plenty of BLOOD, or a _Calid_ WOMB, desirous of _Copulation_, or to such as have their MENSTRUA after the _first_ CONCEPTION.