THE OSSEOUS SYSTEM. 323 



may then be induced no longer to regard Schwann's and my views as 

 antiquated.* 



* [As we have already said, we must deny the existence of endogenous cell-development 

 in ossifying, or any other cartilage. In fact, the process of multiplication of the corpuscles 

 (nuclei (?) of Kolliker, granular cartilage-cells of Tomes and De Morgan) is so clear, that 

 we are at a loss to comprehend how it can be mistaken. What is meant in the text by 

 " contents," as distinct from the corpuscles, we do not know. Messrs. Tomes and Morgan 

 describe the real changes which precede ossification, very exactly in a few words, thus : 

 " Cartilage previous to its conversion into bone undergoes a rapid growth, which takes place 

 principally in the direction of the long axis of the future bone. Each granular cell becomes 

 divided into two, by segmentation transverse to the line of ossific advance. These are again 

 divided and the process repeated from time to time, until in the place of a single granular 

 cell we have a long line of cells extending from the unchanged cartilage to the point where 

 ossification has taken place" (1. c., p. 16). "If attention be directed to the end of the line 

 furthest from the bone, the cells will be found small in size, granular, and with a percepti- 

 ble nucleus, but without an outer wall, distinguishable from the hyaline substance, which is 

 abundant between the contiguous lines, but small in quantity between the cells composing 

 the lines. But if the other end of the line be examined, very different conditions will be 

 observed. The granular cells will be seen to have become rounded in form, to have in- 

 creased to three times their original bulk, and to possess well-marked, circular nuclei. ..." 

 -p. 17. 



So far, our own observations are in perfect accordance with those of Tomes and De Mor- 

 gan. They go on, however, to observe, " in addition to which, each granular cell will have 

 acquired a thick, pellucid, outer wall ;" and with this last statement we can by no means 

 agree. Neither in Man, the Calf, the Rabbit, the Skate, nor in enchondroma, have we been 

 able to see anything of the regular development of such an envelop- in fact, in the great 

 majority of instances, we have convinced ourselves of the absence of anything of the kind 

 there being nothing but a clear space between the corpuscle and the ossified wall of the 

 cavity in which it lies. Bodies corresponding with the lacunal cells cartilage-corpuscles 

 that is, invested by a thick coat of more or less granular, calcareous matter, may indeed 

 often be obtained free; but they arise, like the corresponding bodies in rickety bone, simply 

 from the deposition of calcareous matter in the cartilage-cavity before it has taken place 

 in the matrix, or from a want of union between the two deposits ; and are therefore quite 

 accidental. 



The lacuna, are developed, according to these authors, by the shooting out of the granular 

 cells into processes, and their direct conversion into the lacuna, the nucleus of the granule- 

 cell remaining as the nucleus of the lacuna. On this point also, we must differ from them, 

 and agree with Virchow (1. c., note, 101) and Kolliker (supra, 104), that the development 

 of the canaliculi is, by a process of resolution, quite independent of the corpuscles, which 

 simply diminish in size, and either remain as the so-called " nuclei" of the lacunae or totally 

 disappear. We can especially recommend the Skate (2) as a subject in which to trace the 

 process of formation of lacunae, as the bone is homogeneous and transparent, and in conse- 

 quence of being enclosed in a large mass of firm cartilage, may be cut with ease into very 

 thin sections. We have observed it with great clearness also in enchondroma. 



There is one argument which seems to us conclusive on this point. Wherever the cana- 

 liculi can be seen at all, however young the tissue, they are perfectly clear and transparent. 

 If. however, they were formed by processes of the granular cells, they ought to be granular, 

 and more or less opaque. 



Taking the same view of the structure of cartilage as Messrs. Tomes and De Morgan, 

 then, our view of the nature of the lacunae, resulting from its ossification, agrees with that of 

 Professor Kolliker. Cartilage becomes bone by the deposit of calcareous salts in the matrix 

 and occasionally in its cavities. The lacunae are spaces left round the corpuscles, from 

 which, by resorption, processes the canaliculi, are subsequently developed. If it be asked 

 how it is that the lacunae may frequently be demonstrated both optically and chemically as 



