Page:Cyclopaedia, Chambers - Volume 1.djvu/881

 GEN

•"

( 13+)

GEN

Paffagc from a Privation, or Want cf a fubflantial Form, to the having of fuch a Form. See Subjlantial Form.

The Moderns allow of no other Change in Generation, than what is local: According to them, 'tis only a Tranfpo fition, or new Arrargement of Parts ; and thus, the fame Matter (hall fucceffively undergo an Infinity of Generations.

A Grain of Wheat, e.gr. is committed to the Ground ; this imbibing the Humidity of the Soil, becomes turgid, and dilates to fuch Degree, that it becomes a 'Plant, and, by a continual Acceflion of Matter, ripens by degrees into an Ear; and at length imo new Seed. This Seed, ground in the Mill, appears in form of Flower ; which, mix'd up with Water, makes a Pafle ; whereof, with the Addition of Yeft, Fire &o. 'Bread is generated: And this Bread, broke with the Teeth, digefted in the Stomach, and convey'd thro' the Canals of the Body, becomes Flejh,

Now, in all this Series of Generations, the only thing ef- fected, is a local Motion of the Parts of the Matter, and their fettling again in a different Order ; fo that, in Reality, wherever there is a new Arrangement, or Compofition of Elements, there is a new Generation ; and therefore Gene- ration is reduced to Motion. Sec Element, and Motion.

Generation is more immediately underftood of the Production of Animal and Vegetable Bodies, from Seed, or the Coition of others of different Sexes, but the fame Ge- nus, or Kind. See Animal, and Vegetable 5 fee alfo Sex, &c.

Some of the modern Naturalifts maintain, after Monf. tperratdt, that there is not properly any new Generation : That God created all Things at firft : And that what we call Generation, is only an Augmentation and Expanfion of the minute Parts of the Body of the Seed 5 fo that the whole Species to be afterwards produced, were really all form'd in the firft, and inclofed therein j to be brought forth and ex- clofed to view in a certain Time ; and according to a certain Order and Oeconomy. See Seed.

Thus, Dr. Garden : ' It is molt probable, that the Sta-


 * mina of all the Plants and Animals that have been, or


 * ever fliall be in the World, have been form'd ab origins


 * Mundi, by the Almighty Creator, within the firft of each


 * refpective Kind. And he who confiders the Nature of


 * Vifion, that it does not give us the true Magnitude, but


 * only the Proportion of Things 5 and that what feems to


 * our naked Eye but a Point, may truly be made up of as

8 think this an abfurd or impofTible Thing." Mod. 'tkeor. of Generat.
 * many Parts as feem to be in the whole TJniverfe, will not

The Manner, wherein the Seed of the Male Animal acjs on that of the Female, to impregnate, and render it pro- lifick, has long been inquir'd after 5 and yet remains ftill a Myflery. Some, with Ariflotle, hold the Male Semen to do the Office of a Coagulum 5 and the Female that of Milk : Which fome later Authors have improved on, by fuppoling the Male Seed an Acid ; and the Female an Alcali. Others, confider the thicker Seed of the Male, as the Flower j and the thinner Seed of the Female, as Water, out of which two an animal Pafte is wrought, and baked by the Heat of the Womb. But the Moderns are generally agreed, that what Effect foever the Male Seed produces on the Female, 'tis by Motion and Mechanicks that it produces it.

Generation of Animals, or Animal Generation, is a Procefs in the Oecnnomy of Nature, very difficult to be traced. The Parts concurring hereto, are numerous 5 and their Functions moftly dilcharg'd in the Dark.

The Antients diitinguifti'd two kinds of Generation: Re- gular, called Urn-vocal-, and Anomalous, called alfo Equi- vocal, or Spontaneous.

The firfi was effected by Parent Animals of the fame kind ; as that of Men, Birds, Beafts, &c. The fecond was fuppofed effected by Corruption, the Sun, g£e. as that of Infects, Frogs, $§c. But this latter Kind is now generally ex- ploded. See Equivocal, Spontaneous, Univocal, &c.

There are two principal Theories, or Methods of accounting for the Generation of Animals : The one fuppofes the Embryo, or Fcetus to be originally in the Seed of the Male ; the other, in the Ovum, or Egg of the Female.

The firfi fuppofes Animalcules in the Male Seed, to be the firfi Rudiments of the Fcetus 5 and that the Female only furnifh.es a proper Nidus, and Nutriment to bring them for- wards. See Seed, and Animalcula.

The fecond fuppofes the firfi Rudiments of the Animal to be in the Ova ; and that the Male Seed only ferves to warm, cherifh and ripen the Ova, till they fall off* out of the Ovary into the Womb. See Egg, Ovary, &c.

The firft Syftem is well illuff rated by Dr. Geo. Garden: That Author, upon comparing the Obfervations, and Difco- veries of Harvey, Mcdpighi, 'De Graaf, and Zee-wenhoeck together, concludes it moll probable, " That all Animals are " ex animalculo : That thefe Animalcules are originally in " that they can never come forward, nor be form'd into A- •* nimais, without the Ova in the Female."
 * ' Semine Mo/tiUm, and not in that of the Female 5 but

The If* of thefe Points he argues from the three following Obfervations :

i° That fomething has often been obferved by Malpigbi, in the Cicatricula of an Egg before Incubation, like the Ru- diments of an Animal, in term of a Tadpole. See Cica- tricula.

2 From the fudden Appearance and Difplaying of all the Parts, after Incubation, it feems probable, that they are not then actually formed out of a Fluid j but that the Sta- mina of them have been formerly there exiilent, and are now expanded — The firft Part of the Chick, which is dif- covcr'd with the naked Eye, is the PunBum Saliens, and that not till three Days and Nights of Incubation are paft 5 on the fifth Day the Rudiments of the Head and Body ap- pear. This made Dr. Harvey conclude, that the Blood had a Being before any other Part of the Body, and that from it all the Organs of the Fcetus were both formed and nourifh'd ; but by Malpighfs Obfervations it appears that the Parts are then only fo far extended, as to be made vi- fible to the naked Eye; and that they were actually exiilent before, and difcemable by Glaffes. After an Incubation of 30 Hours, we fee the Head, the Eyes, and the Carina, with the Vertebra:, diflinct, and the Heart. After 40 Hours, its Pulfe isvilibie, and all the other Parts more diflinct, which cannot be difcerned by the naked F-ye, before the Beginning of the fifth Day : From whence it feems very probable, that even the io early Difcovery of thole Parts of the Fcetus by the Microfcope, is not the difcerning of thofe Parts newly form'd; but only more dilated and extended by receiving of Nutriment from the Colliquamentum 5 fo that they feem all to have been actually exiilent before the Incubation of the Hen. And what S-wammardam has difcover'd in the Tranfmutation of Infects, gives no fmall Light to this 5 fince he makes appear, that in thofe large Eruca's which feed upon Cabage, if they be taken about the Time they retire to be transformed into Aurelias, and plunged often in warm Water to make a Rupture of the outer Skin 5 you will difcern, thro' the Tranfparency of their fecond Mem- brane, all the Parts of the Butterfly, the Trunk, Wing, Feelers, gfo folded up : But, that after the Eruca is chang'd into an Aurelia, none of thefe Parts can be difcerned 5 being fo much drench'd with Moiflure 5 tho' they be there actually form'd. See FceTus, Aurelia, &c.

3 As to the Analogy between Plants and Animals: All Vegetables, we fee, do proceed ex Plantula 5 the Seeds of Vegetables being no other but little Plants of the fame kind, folded up in Coats and Membranes : Whence we may infer, that fo curioufly an organiz'd Creature, as an Animal, is not the fudden Product of a Fluid, or Goljiguamectum, but does much rather proceed from an Animalcule of the fame kind, and has all its little Members folded up according to their feveral Joints and PJicatur©$, which, are afterwards en- larged and diftended, as we fee in Hants.

The II d Point, which our late Discoveries have mads probable, is, .hat thefe Animalcules are originally in the Seed of the Male, and not in the Female : For i° There are obferv'd innumerable Animalcula in femine mafcnlino, of all Animals. Leewenboeck has made this fo evident, that there feems little room to doubt thereof.

2 We obferve the Rudiments of a Fcetus in Eggs which have been fcecundated by the Male ; tho' no fuch Thing is vifible, in thofe not fcecundated. Malfighi, in his Obfer- vations, makes it very probable, that thefe Rudiments pro- ceed originally from the Male, and not from the Female.

3 The Refemblance between the Rudiments of the Fce- tus in Ovo, both before and after Incubation, and the Ani- malcule, makes it very probable that they are one and the fame. The fame Shape and Figure, which M. Leewenboeck gives us of the Animalcule, Malpighi gives of the Rudi- ments of the Fcetus, both before and after Incubation $ yea, and even the Fcetus's of viviparous Animals appear fo at firft to the naked Eye ; whence Dr. Harvey acknowledges, that all Animals, even the moft perfect, are begotten of a Worm.

4 This gives a rational Account of many Fcetus's at one Birth, efpecially that of the Countefs of Holland: And how, at leaft, a whole Clufler of Eggs in a Hen are fcecundated by one Coition of the Male. See FceTus.

5 This gives a new Light, as it were,, to the firft Pro- phecy concerning the Mejfiah, that the Seed of the Woman /hall brnife the Head of the Serpent ; all the reft of Man- kind being thus moft properly and truly the Seed of the Man.

6 Q The Analogy already mention'd, which we may ra- tionally fuppofe between the manner of the Propagation of Plants and Animals, does likewife make this probable. Every Herb and Tree bears its Seed after its Kind; which Seed is nothing elfe but a little Plant of that Kind 5 which being thrown into the Earth, as into its Uterus, fpreads forth its Roots, and receives thence its Nouriihment ■ but has its Form within it felf; And we may rationally conjecture fome

fuch