1

By reafon it would be endlefs to mention all the Curiofities obferveable in the Bones, I fhall for a Sample, fingle out only an inftance or two, to manifeft that Defign was used in the Structure of thefe Parts in Man.

The firft fhall be in the Back-bone, which (among many others) hath these two things remarkable. 1. Its different Articulations from the other Joynts of the Body. For here moft of the Joynts are flat, and withal guarded with Asperities and Hollows, made for catching and holding; fo as firmly to lock, and keep the Joynts from Luxations, but withal to afford them fuch a Motion, as is neceffary for the Incurvations of the Body. 2. The difference of its own Joynts in the Neck, Back and Loins. In the Neck, the Atlas, or upper Vertebra, as alfo the Dentata are curiously made, and joynted (differently from the reft) for the commodious and eafie bending and turning the Head every way. In the Tho rax, or Back, the Joynts are more clofe and firm and in the Loins, more lax and pliant; as alfo the Spines are different, and the Knobs and Sockets turned the quite contrary way, to anfwer the occafions the Body hath to bend more there, than higher in the Back. I fhall close this Remark with the ingenious Dr. Keil's Obfervation.

The Structure of the Spine is the very best that can be contrived; for bad it been all Bone, we could have had no Motion in our Back's: bad it been of two or three Bones articulated for Motion, the Medulla Spinalis must have been necessarily brui fed at every Angle or Joynt; befides, the whole would not have been fo pliable for the several Poftures we have occafion to put our felves in. If it had been made of feveral Bones witbyut intervening Cartilages, we should have had no more Use of it, than if it had been but one Bone. If each Vertebra had bad its own diftinct Cartilages, it might have been easily dislocated. And lastly, the oblique Proceffes of each fuperiour and inferiour Vertebra, keep the middle one that it can neither be thrust backwards nor forwards to comprefs the Medulla Spinalis. Keil's Anat. c. 5. § 8.

Compare here what Galen faith of the Articulations, Li gaments, Perforation, &c. of the Spine, to prove the Wildom and Providence of the Maker of Animal Bodies, against fuch as found fault with Nature's Works; among which he names Diagoras, Anaxagoras, Afclepiades and Epicurus. V. Galen de Uf. Part. L. 12. init. and Chap. 11. &c, alfo L, 13. init.

2. The next Inftance fhall be in one or two things, where in the Skeletons of Sexes differ. Thus the Pelvis made in the Belly by the Ilium, Offa Coxendicis and Pubis, is larger in a Female than Male-Skeleton, that there may be more room for the lying of the Vifcera and Fatus, So the Car filage bracing together the two Offa Pubis, of Skarebones, M

Barthez

might take notice of the Joynts (4), their compleat Form adjusted to the Place, and Office they are employed in; their Bandage, keeping them from Luxations; the oily Matter () to lubricate them, and

Bartholine faith is twice thicker and laxer in Women than Men as alfo is the Cartilage that tieth the Os Sacrum to its Vertebra; and all to give way to the Paffage of the Fatus.

Another confiderable Difference is in the cartilaginous Production of the feven long Ribs, whereby they are bra ced to the Breaft-Bone. Thefe are harder and firmer in Women than in Men; the better to fupport the Weight of the Breafts, the fucking Infant, &c.

(4) It is remarkable in the Joynts, and a manifeft Act of Caution and Defign, 1. That altho' the Motion of the Limbs be circular, yet the Center of that Motion is not in a Point, but an ample Superficies. In a Point, the Bones would wear, and penetrate one another; the Joynts would be exceedingly weak, &c. but the Joynts confifting of two large Superficies, Concave and Convex, fome furrowed and ridged, fome like a Ball and Socket, and all lubricated with an oily Subftance, they are incomparably prepared both for Motion and Strength. 2. That the Bones next the Joynt are not spungy, as their Extremities commonly are, nor hard and brittle, but capped with a ftrong, tough, smooth cartilaginous Subftance, ferving both to Strength and Motion.

But let us here take notice of what Galen mentions on this Subject Articulorum unufquifque Eminentiam Cavitați im➡ miffam babet. Veruntamen boc fortaffe non adeo mirabile eft, fed fi confiderata omnium totius corporis offium mutuâ connexione, Eminentias cavitatibus fufcipientibus æquales femper inveneris. Hoe mirabile. Si enim jufto amplior effet Casitas, laxus fane& infirmus fieret Articulus: fi ftriétior, motus difficulter fieret, ut qui nullam verfionem haberet, ac periculum effet non parvum, eminentias offium arctatas frangi: fed horum neutrum factum eft.---Sed quoniam ex tam fecura conftru&tione periculum erat, ne motiones difficilius fierent, & eminentia offium extererentur, duplex rurfus auxilium in id Natura molita eft. 1. Cartilagine os utrumque fubungens, atque oblinens: alterum, ipfis Cartilaginibus humorem untucfum, velut oleum, fuperfundens; per quem facilè mobilis, & attritu contumax omnis articulatio Offium facta eft.---Ut undique diligenter Articulus omnis cu¬ ftodiretur, Ligamenta quadam ex utroque offe produxit Natura. Galen de Uf. Part. 1. 1. c. 157

(I) For the affording this oily or mucilaginous Matter, there

and their own Smoothnefs to facilitate their Motion.

And lastly, I might trace the various Nerves throughout the Body; fent about to miniftef to its various Motions (5). I might confider their Origin (6), their Ramifications to the feveral Parts, and their Inofculations with one another,according to the Harmony and Accord of one Part with ano ther, neceffary for the benefit of the Animal. But fome of those things I have given fome touches up

on

there areGlandules very commodioufly placed near the Joynrs, fo as not to fuffer too great Compreffion by the Motion of the neighbouring Bones, and yet to receive a due Preffure, fo as to caufe a fufficient emiffion of the Mucilage into the Joynts. Alfo another thing confiderable is, that the excretory Ducts of the mucilaginous Glands have fome length in their Paffage from the Glands to their Mouths; which is a good Contri vance, to prevent their Mouths being oppreffed by the Mucilage, as alfo to hinder the too plentiful Effufion thereof, but yet to afford a due expreffure of it at all times, and on all occafions, as particularly in violent and long-continued Mo tions of the Joynts, when there is a greater than ordinary expence of it. See Cowper's Anat. Tab. 79.

(5) There is no doubt to be made, but that the Mufcles receive their Motion from the Nerves. For if a Nerve be out, or ftraightly bound, that goes to any Mufcle, that Mufele fhall immediately lofe its Motion. Which is doubtlefs the cafe of Paralyticks; whofe Nerves are fome of them by Obftructions, or fuch like means, reduced to the fame State as if cut, or bound.

And this alfo is the caufe of that Numnefs, or Sleepiness we find oftentimes, by long fitting or lying on any part. Neither is this a modern Notion only for Galen faith, Principium Nervorum omnium Cerebrum eft, & Spinalis Medulla, Et Nervi à Cerebro animalem virtutem accipiunt--Nervorum utilitas eft facultatem Sensus & Motûs à principio in partes diducere. And this he intimates to have been the Opinion of Hippocrates and Plato. De Uf. Part. 1. 1. c. 16. &paffim.

(6) Dr. Willis thinks, that in the Brain the Spirits are elaborated that minifter to voluntary Motion: but in the Cerebellum, fuch as effect involuntary, or natural Motions fuch as that of the Heart, the Lungs, E. Cerebri Anat. c 15

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(7) Seg

Book IV. on already,and more I fhall mention hereafter (7), and it would be tedious here to infift upon them all.

I fhall therefore only 1peak diftinely to the Locomotive Act it felf, or what directly relates to it.

And here it is admirable to confider the various Methods of Nature (8), fuited to the Occafions of various Animals. In fome their Motion is fwift, in others flow. In fome performed with two, four, or more Legs: in fome with two, or four Wings in fome with neither (9).

And firft for fwift or flow Motion. This we find is proportional to the Occafions of each refpective Animal. Reptiles, whofe Food, Habitation, and Nefts, lie in the next Clod, Plant, Tree, or Hole, or can bear long Hunger and Hardship, they need neither Legs nor Wings for their Tranfportation; but their vermicular, or finuous Motion (performed with no lefs Art,and as curioufly provided for, as the Legs or Wings of other Creatures: this, I fay,) is fufficient for their Conveyance.

Man

(7) See Book V. Chap. S.

(8) To the foregoing, I fhall briefly add fome Examples of the fpecial Provifion made for the Motion of fome Animals by Temporary Parts. Frogs and Toads, in their Tadpoleftate, have Tails, which fall off when their Legs are grown out. The Lacerta aquatica, or Water-Newt, when Young, hath four neat ramified Fins, two on a fide, growing out a little above its Fore-Legs, to poife, and keep its Body upright, (which gives it the refemblance of a young Fish,) which fall off when the Legs are grown. And the Nympha and Aurelie of all, or moft of the Infects bred in the Waters, as they have particular Forms, different from the Infects they produce; fo have alfo peculiar Parts afforded them for their Motion in the Waters: Oars, Tails, and every Part adapted to the Waters, which are utterly varied in the Infects themselves, in their mature State in the Air.

(9) Jam vero alia animalia gradiendo, alia ferpendo ad paftum accedunt, alia volando, alia nando. Cic. de Nat. DeDr. 1. 2. c. 47:

Compare alfo what Galen excellently obferves concerning

the

Man and Beafts, whofe Occafions require a large room, have accordingly a fwifter Motion, with proper Engines for that Service; anfwerable to their range for Food, their Occupation or Bufiness, or their want of Armature, and to fecure them against Harms (10.)

But for the winged Creatures (Birds and Infects,) as they are to traverfe large Tracts of Land and Water, for their Food, for their commodious Habitation, or Breeding their Young, to find places of Retreat and Security from Mifchiefs; fo they have accordingly the Faculty of flying in the Air; and that swiftly or flowly, a long or a fhort time, according to their Occafions and way of Life. And accordingly their Wings, and whole Body, are curiously prepared for fuch a Motion; as I intend to fhew in proper place (11).

Another remarkable thing in the motive Faculty of all Creatures, is the neat, geometrical Performance of it. The most accurate Mathematician, the moft skilful in mechanick Motions, can't prescribe a nicer Motion (than what they perform) to the Legs and Wings of thofe that walk or fly (12), or to the Bodies of thofe that creep (13). Neither

can

the Number of Feet in Man, and in other Animals; and the wife Provifion thereby made for the Ufe and Benefit of the refpective Animals. De Uf Part. in the beginning of the third Book.

(10) As I fhall hereafter fhew, that the indulgent Crea tor hath abundantly provided for the fafety of Animals by their Cloathing, Habitations, Sagacity and Inftruments, of Defence; fo there appears to be a Contemperament of their Motion with thefe Provifions. They that are well-armed and guarded, have commonly a flower Motion; whereas they that are deftitute thereof, are fwifter. So alfo timid. helpless Animals are commonly fwift; thus Deer and Hares but Animals endowed with Courage, Craft, Arms, &. commonly have a flower Motion.

(11) See Book VII. Chap. 1. (12) See Book VII. Chap. (13) See Book IX. Note 3.

1. the end.

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(14) Siqui