BON 



B O N 



fidered as a very Urango peculiarity, were not tlie minute 

 contiguous nutrient arteries to inofculate with one another. 

 The writer of this article is of opinion, that they do in this, 

 as in other inftances, for it is conunon in amputation to cut 

 pffthe trunks of the medullary arteries, and yet the marrow 

 of the remaiiiinfr bone does not perirti ; and, again, the bone 

 may be injefted from the medullary artery alone. We may 

 next inquire into the ufes of the marrow. Havers thougl'.t 

 that it traiifudcd through the bo^ne, and by this means pre- 

 vented it from becoming brittle ; nay, he even defcribcd the 

 pores through whicii fuch tranfudation was fuppofed to take 

 place. The cells, however, which contain the marrow are 

 perfeft vcficles ; and we know that no tranfudation of con- 

 tained fluids takes place through the membranes which con- 

 tain them during life, though in conlequence of putrefaftion 

 it does afterdcath. If a bone be depiived of its periofleum 

 in a living body, no tranfudation of oil from its furiace takes 

 place ; and even after de?,th a recent bone may be deprived of 

 its periofleum, and put in warm water for a confiderable 

 time, and yet no fuJden tranfudation of oil from the hirface 

 will take plact, as might be cxpefted if there were natural 

 channels for this purpofe. Tlie canals which Havers de- 

 fcribed, are probably the palTages through which the vefieU 

 are tranfmitted. If then this opinion of the ufe of the mar- 

 row be unfounded, we have dill to inquire, for what purpofe 

 is "t defigncd ? The utility of the bones being formed as 

 they are, fmall and tubular iu their middle, expanded and 

 fpongy at their extremities, has been already explained. If 

 ^ then fpaccs are ncccfTarily left in their interior parts, thofe 

 fpaces muil be filled with fomething, for they cannot be left 

 void, or the immenfe prefTure of the atmofphere would crufli 

 their parietes, and abolilh the vacuum, '^riiere is no matter 

 in the animal body more fuitable to fill their fpaces than the 

 marrow ; and it is to be regarded as a part of the adipofe 

 fyflem of the animal. Iu corroboration of this remark, it 

 has been oblervcd, that iu impoverillied and dropfical fubjefts, 

 where there is no fat in other parts, there is likewife none 

 even in the bones i and if a bone be fawn, and the medullary 

 cells broken down, to that the fluid which they contain may 

 drop out upon paper, that it will not penetrate it, and render 

 it trAnfpareiit like oil ; bat, on the contrary, that it will en- 

 cruft upon if, from its being of a gelatinous nature, like that 

 fluid which is found in the inter"iices of the common reticular 

 or cellular fubftance. From the clrcumftances which have 

 been detailed in the foregoing account, viz. the great and 

 general vafcularlty of bones ; — the qrantity of fott fubllance 

 exifting in every part of them ; — their growth and mutation 

 of form in difeafe, &;c. ; — it is natural to conclude, that there 

 cxift in the compofition of every bony fibre, arteries for its 

 formation, ab.'orbents for its removal, ce!lul:it fvibftance for 

 the connexion of its parts, and nerves to give animation to 

 the whole. In this view of the fubjed, we perceive no 

 elTential difference of ftruClure between bones and other parts 

 of the body ; nor do we expect any effenti^l ditTcrence in the 

 funflions of their nutrient, and other velTels. We naturally 

 conclude that bony fibres are formed and repaired, and that 

 they undergo mutation or removal in the fime manner, and 

 from the fame caufes, that foft parts do. Mr. Hunter, how- 

 ever, from obferving the Ihiated appearance of the bones of 

 animals, who have been at one time fed with madder, and at 

 another with common food, and obferving that the exterior 

 llria was red if the animal was killed after having been for 

 fome time fed with madder, and white if it had only taken 

 Its ordinary food, concluded tliat bones grew by a dcpolkion 

 ou their fnrfacc, and a correfpondent removal of the internal 

 part of the walls of the bone. Mr. Hunter alfo, to invelli- 

 gate the truth of Da Hamcl's opinion refpeding the growth 



of bones, bored two liolcs in the tibia of a pig, one near the 

 upper end, and the oth.er neartlie lower ; the fpacc between 

 the holes wa? exaftly two inches ; a fmall leaden Paot was in- 

 fertcd into each link : when the bone had been incieafed iu its 

 length by the growth of the aiiiuial the pig was killed, and the 

 fpacc between the two fhots vv;i.se\aclly two inches. Mr. Hun. 

 ter's experiments and "pinions are publiilitd by Mr. Home in 

 thefecondvolumeof Tranfaftions ot a Society for the improve- 

 ment of Medical and Chirurgical Knowledge. We forbear 

 to give a more detailed account of tlicm, ov enter into 

 any difcuflion of the fu'njeft, but refer the reader to the ori. 

 ginal paper, becaufe we believe that no theory will be foundi 

 on coniideration, to be adequate to account tor the pheuo- 

 mena of the growth and difeafes of bones, except that 

 which admits the bony fibres to be ot the ianic ftrufture as 

 the foft fibres of the body, and confequently concludes that 

 both are formed, removed, and renovated in the fame nianner. 

 We fubjoin fome references to the inftruitive works on the 

 flruttureof thebones. Albini iconesofiium fcetusjcui accedit 

 ofleogen. brevis hlRoria. — Annot. Acad. J. G. Walter 

 handbuch von den knochen. Reichel Diflf. de offium ortu 

 & ftruttura in .Saudif. thefaur, diff. vol.ii. Bochmer inlli- 

 tutiones olleologlca;. Blumenbach Gefchichte und bcfchrei- 

 bung der knochen. The works of Ruytch. Nefbit's hu- 

 man olleogeny explained. Kerckring anthropograph. ri- 

 trograph. & olleogenia foctuum. Du Hamel in memoires 

 de I'acad. des Sciences, 1742. Haller. in op. minor, 

 torn. ii. 



Bone, in Chanijlry and the Arts, The analyfis of bone, 

 and the produfts obtained from it by various chemical pro- 

 celfes, deferve confiderable attention, as this great clafs of 

 animal fubflanccs ranks among the moil important to the 

 chemift. 



So great a fimilarity is found in the compofition of the 

 bones of different animals, that their properties may firft be 

 defcribed generally. 



Bone, when firll taken from the animal, is moifl and 

 greafy on its furface ; and if cylindrical, it contains a quan- 

 tity of the peculiar fat called mnrroiu. When this is Sepa- 

 rated, and the bone expofed to the air, it gradually dries, 

 becomes brittle and whiter ; but the articulating heads long' 

 remain moift, grtafy, and yellow. When once dry, and 

 kept in a dry and airy place, they are fcarcely fufceptiblc or 

 further fpontaneous alteration. 



The effect ot mere heat on bone has long been known to 

 chemillry and the arts, as furnifhing forae very important arti- 

 cles of chemical manufacture. Heated in the open air, bona 

 firlt becomes oily and yellow, gives out a watery vapour, to 

 which fucceeds a thick, denfe, fetid fmoke, which readily 

 takes fire, and when oace kindled, affords heat enough, when 

 the bones are in fulTicicnt quantity, to complete the entire 

 calcination, which lalls for many hours, during which they 

 become fuccefTively black and carbonaceous, brittle, and ac 

 iall, when every thing combuflible is confumed, they remain 

 nearly white, friable, light, and extremely porous or cellular 

 in texture, and retaining their original fhape and bulk. This 

 procefs of burning bones in the open air, in large heaps, is 

 performed near great towns for the fake of the earthy fait 

 bonc-q/b, which is left behind, and forms on an average about 

 half the weight of the fre/h bone. It is compofed chiefly of 

 phofphat of lime, and is ufed by the afiayers as the material 

 for cupels, and for a few other pnrpofes. 



But the volatile produAs which are wafted in the above 

 procels, are highly valuable when the bones are dilUllcd in 

 clofe veflVls, without addition as before, but with a proper 

 apparatus to receive and condenfe the volatile produfts. In 

 thefe circumftances, with a heat at firft gentle, but gradually 



iiicreafing. 



