298 THE SOLIDS. 



by means of dilute hydrochloric acid, exhibits a delicate 

 structure, the precise nature of which it is not easy to deter- 

 mine ; its surface will be seen to be marked out into innumer- 

 able lozenge-shaped spaces, one side of each of which is 

 concealed by a dark shadow, and the divisions between which 

 are without shadow. (See late XXXIII. fig. 4.) 



This interesting structure was first distinctly pointed out 

 by Dr. Sharpey *, who conceives that it arises from the cross- 

 ing and union of fibres ; these, however, cannot be traced out 

 and displayed as separate fibres, owing, it is presumed, to 

 their being united or fused together at the points where they 

 cross each other ; it sometimes happens, however, that at the 

 torn edge of a lamella a short projecting process may be 

 seen which presents much the aspect of a true fibre, f 



The appearance presented by a lamella thus figured might 

 be compared to the engine-turned case of a watch, and it 

 might also be conceived that it was produced by the union 

 of a number of diamond-shaped cells, and not by the crossing 

 of fibres. 



One argument in favour of the fibrous constitution of the 

 lamella? may be derived from the fact that the cancelli of 

 bone in process of development clearly exhibit a fibrous struc- 

 ture. 



Cross sections of the lamellae may also sometimes be ob- 

 served to be marked with short and radiating lines, which 

 most probably depend upon the structure already noticed. 



The osseous lamella? are likewise perforated necessarily 

 with numerous minute apertures occasioned by the canaliculi 

 of the bone cells, and which when seen with a low power 



* Quain's Anatomy, 5th edition, part ii. p. cxlii. 



f It would appear to be probable from the following quotation that 

 Henle had seen the structure above described. " The lamellae examined 

 on their flat side have appeared to me to be generally hyaline or finely 

 dotted, but sometimes also fibrous ; the fibres are either pale and as 

 though composed of grains, or obscure and rugged ; one never succeeds 

 in isolating them for a certain space, because they are branched, inter- 

 woven, and in a word perfectly identical with the fibres of fibro- 

 cartilages." 



