Proceedings of Public Societies. 



244 



under observation, and in tiicse a mem- 

 branous lining- was very readily discern- 

 ed, tiie iiijected state of tlie parts ren- 

 dering tlio divided edge of the ir.embra- 

 nous tube very obvious. Jn some in- 

 stances this membrane became still more 

 evident, by its having been y)arlially 

 separated from the divided edge of the 

 canal. 



Where the canals wcie found to be 

 divided longitudinally, liie membranous 

 lining was, in general, stiil attached to 

 the sides of the tube, and the beautiful 

 appearance of tlic iiijecicd membrane 

 •was rendered still more brilliant by the 

 abundance and crystalline Iranspareucy 

 of its natural mucous secretion. 



In many parts of the cartilage »rhere 

 the lining of the canals was finely in- 

 jecteiU there was still no appearance of 

 distinct vessels, allhongii in those canals 

 that were opened at their origin upon 

 the external surface of the cartilage, a 

 distinct artery, full of thcinjccted n.atter, 

 luight generally be traced, passuig in- 

 wards to some extent. 



In the more internal canals, the usual 

 appearance of the membranous sheatli, 

 luider the microscope, was such as it 

 would have been if the injection had 

 passed out from the vessels, and become 

 dispersed in the cellular texture of a line 

 membrane; had so peculiar an appear- 

 ance arisen from the accidental rupture 

 of the coats of the arteries, the injected 

 matter must have been detected in 

 masses, which was not iu any instance 

 tlie case. 



In those canals that were divided 

 obliquely, the finely and equally in- 

 jected membrane had the appearance 

 of an uniformly scarlet tulio; and by iti- 

 creasing the magiiitying power to a very 

 l)igh degree, the individual particles of 

 the ver.million not only became visible, 

 Lut were seen most distinctly; they 

 were every where found to be very 

 thinly and evenly scattered, indicathig 

 the most equal dispersion of the colmn-- 

 ing matter througiiout every piirt of the 

 jHembrane. 



la prosecuting this part of the in- 

 quiry, a considerable difficulty at fir.st 

 arose out of the following circumstance. 

 The heat of the water, in which the pre- 

 paration was laid previous to its beino- 

 injected, had so far loosened the mem- 

 branes fiom the sides of the canals, that 

 in the subsequent operation of dividing 

 tlie cartilage into sections, they were 

 torn from their natural situation, and 

 were consequently found in many parts 

 jnore or less collapsed. Tiicse coUapsed 



[Oct. 1, 



membranes had, under the microscope, • 

 very much the appearance ot injected 

 arteries, and were at liist considered as 

 such, but siib:;cqueat and more atten- 

 tive observation soon enabled me to 

 correct this mistake. 



From Jlio foregoing observations I 

 think mysi-ilf warranted in drawing the 

 following conclusions. 



1. 'J'hat, in the mammalia, the first rn- 

 dinients of ossification in the long lK>nes 

 are the cfFcct of a secreting power in the 

 arteries, upon the internal surface of the 

 periosteum, which produce a portion of 

 a hollow cyliiitiir; this form of bone 

 having been iouiid antecedent to the 

 evolution of any cartilaginous structure. 



2. 'I'hat, at a certain stage of the pro- 

 cess, the mode of operating is changed, 

 in order that it may proceed more expe- 

 ditiously. A cartilage is formed, which, 

 by the nature of its organization, and by 

 admitting of a specific provision of ca- 

 vities and canals, lined with vascular 

 membranes, which secrete an abundant 

 store of gelatinous matter, is adapted to 

 this particular purpose; while, at the 

 same time, it serves to determine the 

 futuie figure of the extremity of the 

 bone, by establishing and conducting the 

 ossification within its own substance. 



3. That, from the appearance and 

 texture of cartilage, when examined- 

 under the microscope, it may be de- ' 

 fined — an even and linely granulated 

 albuminous ujatter, deposited in the in- 

 terstitial spaces of an exceedingly clastic 

 bed of a semi-transparent reticulated 

 structure, which is apparently a modi- 

 fication of gelatin. 



4. 'I'hat from the period when the 

 ossification proceeds in the mode above 

 described, by the medium of cartilage, 

 the process is continued iu the same 

 uniform manner till it has completed 

 the growth of the bone. The growth 

 of the epiphyses, and their union with 

 the ends of the bone, are also eflected 

 by the same means. 



5. That the ossific matter in the cy- 

 litidrical bones is deposited primarily ia 

 the form of fine thin tubular plates; a 

 mwie of deposition of all others the 

 most favourable for their being subse- 

 quently remodelled, and for facilitating 

 all the subsequent changes of .structure 

 they arc destined to undergo. 



6 That, while the circulation in the 

 capillary arteries, situated between the 

 cartilage and bone,' must provide the 

 phosphate of lime, the principal agent in ' 

 extending the cylinder, and in eliecting 

 tbe .subsequent progressive changes of 

 structure. 



