86 



BONE. 



Fig. 50. 



by Virchow, each lacuna is occupied by a nucleated cell, or soft 

 corpuscle, which sends branches along the canaliculi ; and later 

 observers (Rouget, Neumann,) state that they have been able to detach 

 the proper osseous wall of the lacuna and its appertaining canaliculi 

 after decalcification, and to obtain it separate Avith its included corpuscle. 

 It can scarcely be doubted that the protoplasm of the nucleated cor- 

 puscle takes an important share in the nutritive process in bone, and 

 very probably serves both to modify the nutritive fluid supplied from 

 the blood and to further its distribution through the lacunar and canali- 

 cular system of the bony tissue. Virchow considers that the corpuscles. 

 of bone are homologous with those of connective tissue : to this it may 

 be added that the enclosing lacunte and canaliculi may be looked upon 

 as corresponding to the cell-spaces (Saft-canfilchen) of that tissue. 



To return to the lamelkc. AVith a little pains, thin films may be 

 peeled off in a longitudinal direction from a piece of bone that has been 

 softened in acid. These for the most part consist of several lamina3, as 

 may be seen at the edge, where the different layers are usually torn un- 

 equally, and some extend farther than others. Examined in this way, 

 under the microscope, the lamellas are seen to be perforated with fine 

 apertures placed at very short distances apart. These apertures were 

 described by Deutsch,* but they have not much attracted the notice 

 of succeeding observers ; they appear to be the transverse sections 

 of the canaliculi already described, and their 

 relative distance and position accord sufliciently 

 with this explanation. According to this view, 

 therefore, the canaliculi might (in a certain 

 sense) be conceived to result from the apposi- 

 tion of a series of perforated plates, the aper- 

 tures of each plate corresponding to those of 

 the plates contiguous with it; in short, they 

 might be compared to holes bored to some 

 depth in a straight or crooked direction through 

 the leaves of a book, in which case it is plain 

 that the perforations of the adjoining leaves 

 would correspond ; it being understood, how- 

 ever, that the passages thus formed are most 

 likely bounded by proper parietes. The aper- 

 tures now referred to must bo distinguished 

 from larger holes seen in some lamellae, which 

 give passage to the perforating fibres to be 

 mentioned further on. 



But the lamella have a further structure. 

 To see this, the thinnest part of a detached 

 shred or film must be examined, as shown in 

 figs. 50 and 52 ; it will then appear plainly 

 that they are made up of transparent fibres, 

 decussating with each other in tlie form of an 

 exceedingly fine network. The fibres intersect 

 obliquely, and they seem to coalesce at the 

 points of intersection, for they cannot be teased out from one 

 another ; but at the torn edge of the lamella they may often be seen 



Tig. 50. — Thin Layer 



PEELED OFF FROM A SoKT- 



ENED Bone, as it appears 



UNDER A JLiGNIFi'ING 

 POWER OP 400. 



This figure, wliich is in- 

 tended to represent the reti- 

 cular structure of a lamella, 

 gives a better idea of the 

 ofcject when held rather 

 farther off than usual from 

 the eye. 



* De Penitiori Ossium Structura. Wratisl. 1834, p. 17, Fig. 6. 



