A NEW 
Preliminary Effay on Generation. 
IT feems requifite that zoologifts fliould confider animals in their nafcent ftate, before they furvey them in their ma- 
turity; that they fhouid trace them from the more early periods of their exiftence; and give a general view of thofe 
diverfitics in their generation which diftinguilh one clafs from another, before they exhibit them as poffpfling the mofl: 
perfcft faculties their rcfpedive natures will permit, or performing thole fundllcns for which Providence leems to have 
peculiarly adapted them. In this effay, therefore, we ill all keep this objeft and this duty folely m view; and, with a 
philofophic apathy, defcribe circumllances and fcenes which the nature of our undertaking requires at our hands, and 
which the fenfual alone can pervert to indecency. 
With that humility of mind which the refleftion is calculated to hifpire, we mufc confefs, that a time has been, when 
the proudeft and noblefl: animal has participated in the fame imbeciiiiy with the meaneft reptile ; and, wiiile yet a candi- 
date for exiftence, was equally helplefs and contemptible. In their incipient ftate, all are upon an equality ; the infedl 
and the molt acute philofopher being equally infenfible, clogged with grofs matter, and unconfcious of exiftence. Wherei 
then are we to commence our hiftory of thofe beings which make iuch a diftinguifhed figure in the creation? Or, 
where lie thofe peculiar charafters in the parts that confpir^ to form an animated nature, that mark one animal as deftined 
to grovel in the duft, and another to glitter on the throne? 
The philofophers of every age have attempted the fokuion of this queftion, which has ever been a fubjedl of curiofity : 
they have, indeed, formed many rational fuppofitions, and made confiderable advances; but ftill certainty is wanting to 
confirm their hypotheies, and theenqwiry remains unfoived with phyfical precifion. In tracing Nature to her m.ift hidden 
receiTes, lire becomes too minute or obfcure for our iufpeftion ; fo that we find it impolTible to mark her firll differences, 
to difcover the point where animal life begins, or the caufe that conduces to fet it in motion. We know little farther, than 
that the grea-eft number of animals require the concurrence of a male and female to re-produce their kind ; and that thefe 
diftindly and invariably are found to beget creatures of their own fpecies. But curiofity has been aftivrly, thoueh un- 
fi'.cceibful!}', employed in trying to difcover the immediate refult of this union ; how far each fex contributes to the be- 
llowing animal life; aiid whether we are moft indebted for the privilege of our exiftence to the exertions of the male or 
the feiiiale. 
Hippocrates was of opinion, that fecundity proceeded from a commixture of the feminal liquor of both fexes, each of 
which equally contributed to the formation of the incipient animal. Ariftotle, on the other hand, would hare ihefeminal 
liquor in the male alone to contribute to this purpofe; while the province affigned to the female by this naturalill was to 
fuppiy the proper neurilhment for it's fupport. 
Such were the opiriions of thefe fathers of philofophy; and thefe continued as the facred and inviolate belief of 
Katuralift.= and fchoolmen for a number of fucceeding ages. 
At length, Stena and Harvey, taking anatomy for ihfir guide, whereas the world had before proceeded on fpeculatlon* 
siForded mankind a nearer view of nature juft advancing into animation. Thefe obferved, in all fuch animals a' produced 
their young alive, two glandul.ir bodies, near the womb, refembling that ovary, or clufter of fmall eggs, which is found 
in fowls; and from the analogy betwixt both, they gave thefe alfo the appellation of ovaria. As thefe refmbled eggs, 
by no unnator.il conclufion, they imagined them deftined for the fame ofRces ; and, therefore, they were induced to think 
that all animals, of v^h.it kind foever, were produced from eggs. 
At firft, however, iliere was fome oppofitlon made to this fyftem ; for, as thefe ovaria were feparate from the womb it 
was objected, that they could not, in any evident lefpeil, be conducive in replenifliing that organ, with which they had 
no vifible communication. But, on more minute infpedion, Trallopius, the celebrated anatomift, perceiv ed two tubular 
veflels depending from the womb, which, like the horns of afnail, pofteffed an inherent power of erecting themfelves, of 
fmbr;icing the ovaria, and of receiving the eggs, in order to be fecundated by the feminal fluid. 
This difcovery feemed, for a long time, to fix the opinions of philofophers, and to terminate conjedure. The doftrine 
of Hippocrates was re-eftablifhed, and the principal bufinefs of generation was afcribed to the female. 
This remained likewife as an eftabliftied opinion for fome time ; but Lewenhoeck, once more, lliook the whole fyftem^ 
. and produced a newfchifm among the admirers of abftrufe fpeculation. On examining the feminal liquor of a vaft num^ 
her of male animals with microfcopes, by which his figh.t was afiifted far better than that of any of his predeceffors had 
been, he perceived therein an infinite variety of little living creatures, like tadpoles, very brifk, and floating in the fluid, 
with a fceining voluntary motion. Each of thefe, therefore, was confidered as the rudiments of an animal, fimilar to that 
from which it was produced ; and this only required a reception from the female, together with proper nourilhment, to 
complcat it's growth. 
The buiinefs of generation v/as now given back to the female a fecond time, by many; while others fufpended their 
afllnt, r.p.dchofe rather toconfefs ignorance than embrace delufive appearances. 
!n this manner has the difpute continued for fcveral ages; fome accldent.:il difcovery ferving, at intervals, to renew 
the deb;:te, and revive curiofity. It was a fubjecl where fpeculation could find much room to difpiay itfelf; and M. de 
BufTon, who was fond of hypothefes, could not overlook fuch an opportunity of giving fcope to his propenfity. Ac- 
cordingly, this moft elegant and moft pleafing of all naturalifts difcovered, by the aififtance of the microlcooe, that not 
only the feminal liquor of males, but alfo of females, abounded with thefe little living animals; and that they appeared 
equally briik in either fluid. Thefe he takes not to be real animals, but organic particles, which, being fimple, cannot be 
r<iiu to be organized themfelves, but to go to the compofition of all organized bodies whatever : in the fame manner as a 
tooth in the wheel of a v/atch, cannot be denominated either the wheel or the watch, and yet contributes to the fum and 
perfection of the machine. 
According to this naturalill, thefe organical particles are difli'ufcd through all nature; ar,d aie found not onlv in the: 
feminal liquor of animals, but in moft other fluids in the parts of vegetables, and all parts of animated nature. As they 
happen, therefore, to be differently applied, they ferve toconftitute a part of the anim.al or the vegetable, whofe growtli 
they help to encreafe, while the fuperfluity is throv/n off in the feminal liquor ofboth fexes, for the reproduction or gene- 
ration of other animals or vegetables of the fame fpecies. Thefe particles aflume different figures, accordino- to the 
recep;rfc!e into which they enter: falling into the womb, they unite into a fcctus ; beneath the bark of a tree thev 
pullulate into branches; and, in fliort, the fame particles that firft formed the animal in the wcmb, contribute to encreafe 
it's growth after parturition. 
But let us attend a v»hile to the arguments of this eloquent author to eftablifli his principles : and when the envy that 
waits on living m.erit is extinft, it is more than probable his fyftem will univerfaily prevail. 
♦ The expanuon and growth,' fays he, < of the different parts of man's body, being effected by the intimate penetration 
of organic particles, analogous to each of thole parts, all the organic particles. In early life, are abforbed, and entirely 
employed in unfolding and augmenting his different members. But, v/hen the body of man has attained'to nearly it's 
fuii fize, he requires not the fame quantity of organic particles; the furplus is therefore fent from all parts inio refervoirs 
deftined for their reception. Thefe refervoirs are the teftes and feminal veffels. At this very period, when the growtli 
of the body is nearly compleatcd, puberty commences, and every pheaoraenon atteadiag it difcovers a fuperabum ance 
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