BOXE. 



fluid supplied from the blood and to further its distribution through the 

 lacunar and caualicular system of the bony tissue. Virchow considers that 

 the corpuscles of bone are homologous with those of connective tissue. 



To return to the lamellae. With a little pains, thin films may be peeled 

 off iu a lougitudin.tl direction from a piece of bone that has been softened 

 in acid. These for the most part consist of several laminae, as may be 

 seen at the edge, where the different layers are usually torn unequally, and 

 some extend farther than others. Examined in this way, under the micro- 

 scope, the lamellae 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 me to be the transverse sections of the caualiculi already de- 

 scribed, and their relative distance and position accord sufficiently with 

 this explanation. According to this view, therefore, the canaliculi might 

 (in a certain sense) be conceived to result from the apposition of a series 

 of perforated plates, the apertures of each plate corresponding to those of 

 the plates contiguous with it ; jn 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 always understood, however, that the 

 passages thus formed are bounded by proper parietes. The apertures now- 

 referred to must be distinguished from larger holes seen in some lamellae, 

 which give passage to the perforating fibres to be mentioned further on. 



But the lamellae have a further structure. To 



Fig. XLV. 



see this, the thinnest part of a detached shred 

 or film must be examined, as shown in figs. XLV. 

 and XLVII. ; it will then appear plainly that they 

 are made up of transparent fibres, decussating 

 each other in 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 separate for a little way, standing out like 

 the threads of a fringe. Most generally they 

 are straight, as represented in the figure ; but 

 they are not always so, for in some parts they 

 assume a curvilinear direction. Acetic or hydro- 

 chloric acid causes these fibres to swell up and 

 become indistinct, like the white fibres of con- 

 nective tissue ; care must therefore be taken 

 in their examination that the remains of the 

 decalcifying acid be removed from the tissue, by 

 maceration in water or in solution of an alkaline 

 carbonate. Moreover, the fibro-reticular struc- 

 ture is not equally distinct in all parts where 

 its presence is recognisable ; for in some places 

 it is less decidedly marked, as if the fibrillation 

 were incompletely developed resembling in this 

 respect the areolar and fibrous tissues. 



In many instances the lamellae are perforated by fibres, or rather bundles 



Fig. XLV. THIN LATER 



PEKLKD OFF FROM A SOFT- 

 ENED BONE, AS IT APPKARS 

 UNDER A MAGNIFYING 

 POWER OF 400. 



This figure, which is in- 

 tended to represent the reti- 

 cular structure of a lamella, 

 gives a better idea of the 

 object when held rather 

 f irther off than usual from 

 the eye. 



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



