432 



BONE, NORMAL ANATOMY. 



denominated reticular or cancellated. Such a 

 distinction is useless. There is no line of 

 demarcation between them. 



At first view a great difference appears to 

 exist between the compact and the spongy 

 substance, but in reality this is not the case. 

 The degree of condensation is the only dis- 

 tinction. The spongy substance would become 

 compact were the sides of its cells pressed 

 together, and the compact would become spongy 

 or reticular were its texture loosened by en- 

 larging the minute cells which may be detected 

 even in it. Such changes actually occur by 

 the processes of absorption and deposition in 

 growing bones. In the perfect bone the cells 

 are compressed towards its middle to diminish 

 its bulk, and thereby to accommodate the bel- 

 lies of the muscles ; and they are expanded at 

 its ends for the purpose of giving security to 

 the joints by a more extensive surface, and 

 allowing more room and power to tendons, &c., 

 whilst the osseous matter in equal lengths of 

 bone, whether at centre or extremity, is of nearly 

 equal weight. The surface of bone in many 

 places presents a striated appearance; and small 

 holes or canals are seen on it especially near 

 the ends of long bones. 



Simple inspection of dried and divided bone 

 carries us thus far in the knowledge of its 

 structure. But the question still arises, what 

 is the arrangement of the particles which com- 

 pose the compact and spongy tissues ? Is 

 bone laminated, or fibrous, or cellular? or 

 does it partake of a texture in which these 

 three varieties of disposition are to be found ? 

 One might imagine there could be no great 

 difficulty in answering these questions, where 

 bone is so readily procured, so easily pre- 

 served, and admits of such varied modes of 

 examination. It can be viewed in the living 

 subject, or after death while fresh, or when 

 prepared by injection, or when all its moisture 

 is removed. It was long ago discovered to 

 consist of an earthy and an animal portion, 

 either of which can be removed, leaving the 

 other undisturbed in its original form. Yet, 

 with all these " appliances and means to boot," 

 anatomists have entertained opposite opinions, 

 and are not yet quite agreed upon the subject. 

 Malpighi, the first author who deserves to be 

 mentioned, thought that bone consisted of 

 fibres and filaments with an intermediate os- 

 seous juice : " constat igitur, ossa coagmentari 

 filamentis, et fibris per longum ductis in rete 

 implicitis, quae affuso osseo succo ferrumi- 

 nantur in solidam densamque ossis naturam." 

 (Op. Posth. p. 47. Lond. 1636.) He also 

 allowed the existence of lamellae, though he 

 does not put forward its lamellar structure in a 

 prominent way.* Gagliardi adopted his no- 



* We are told by an interesting writer that Mal- 

 pighi compared these lamellae to the leaves of a book. 

 Could this writer have taken " libri," in the fol- 

 lowing passage, to mean book instead of bark, of 

 which last Malpighi had just been speaking ? 

 " Part incremento procedit natura in ossiurn aug- 

 mento. Foetus ossa, et cranium precipue, fila- 

 mentorum progressum exhibent ; haec non omnino 

 sibi parallela sunt, et hinc inde breves appendi- 



tions of a laminated structure, but made 

 additions, from which Malpighi, at a subse- 

 quent period, expressed his dissent. He exa- 

 mined bones long exposed to the weather, or 

 softened by boiling, and concluded that they 

 were formed of plates, (lamellae, squamulae, 

 bractese,) held together by processes, in the 

 form of nails, the shape and direction of which 

 he minutely describes.* Clopton Havers found 

 bones composed of plates connected by an 

 osseous juice, with pores which ran, some 

 transversely through the plates, others longitu- 

 dinally through the entire length of the bone.f 

 Leuwenhoeck thought that the filaments of Mal- 

 pighi were hollow tubuli.J Duhamel observed 

 concentric layers as in wood. Haller says, " Fi- 

 brosum est (os) sive in laminas et fila divisum 

 quae sulcis separantur."|| And Monro lays it 

 down that " bones are composed of a great 

 many plates, each of which is made up of 

 fibres or strings united by smaller fibrils."1|" 

 About the close of the eighteenth century the 

 celebrated Scarpa published his work " De 

 penitiori ossium structura," in which he com- 

 bats former opinions, and asserts that bone is 

 in every part of a cellular or reticular texture. 

 In the first place he shows that we have no 

 proof of its lamellated structure ; the appear- 

 ances produced by calcination, the weather, 

 disease, &c. on which former anatomists relied, 

 proving nothing. Calcination is a rude pro- 

 cess, and acts with different power on the dif- 

 ferent parts ;of the same bone as they vary in 

 density, and divides them irregularly as it 

 happens to overcome their force of cohesion. 

 The same thing may be said of the weather. 

 And exfoliation takes place in the skin, whose 



culas filamentosas promunt, quibus invicem col- 

 ligata rete efformant parum a libri natura distans, 

 cujus potiores areas et tota fibrarum compages 

 exsudante osseo succo repletur et tumet." 

 Here we have a tissue of fibres and filaments run- 

 ning in various directions, and forming a net-work 

 not unlike a book ! ! From this quotation, indeed, it 

 might be thought that our author entirely denied 

 the existence of plates. However, in the next 

 sentence he speaks of plana, lamellae, and bractece : 

 {< Successivis incrementis nova fibrarum plana su- 

 perinducuntur, quae praaexistenti lamellce osseo 

 agglutinata succo, debitam molem et firmitatem 

 excitant. Patent autem singula plana resolutione 

 facta per longum ossium maceratione ; integras 

 namque osseae reticulares bractece evelluntur. 

 In abortibus vero in cranio inchoatum rete evi- 

 denter conspicitur." Anatome Plantarum. Op. 

 Omn. p. 19, Lond. 1686. 



* tl Natura prudens ossiculis eas transfixit." 

 The nails were of four kinds for the outer plates, 

 viz. " pprpendiculares acuti, perpendiculares ca- 

 pitati, oblique situati, et inflexi angulum effor- 

 mantes.'' The inner plates, forming the spongy 

 substance, differed from the outer, and were of 

 three kinds, the corrugated, the perforated or cri- 

 briform, and the reticulated. These had a system 

 of nails peculiar to them : " alia sine cuspide, 

 plurima ramusculos rescissos efformant, nonnulla 

 breviora." Anatome Ossium. Lugd. Bat. 1723. 



t Observationes de Ossibus, Auctore Cloptone 

 Havers. Amstel. 1731. 



t Opera Omnia, Lugd. Bat. 1722. 



Mem. de 1'Academie Roy. des Sciences, 1739, 

 41, 42, 43. 



|J Opera Minora, torn. ii. Laus. 1767. 



1f Monro's Works, Edin. 1781. 



