714 



THE MIC ROSC >PE. 



Professor Quekett's paper in an early number of the 



Micros. Soc. Trans, gave an 

 excellent account of the " In- 

 timate structure of Bone." To 

 this paper we are indebted 

 for the following microscopical 

 investigation of bone : — 



Bone consists of a bard and 

 soft part ; tbe bard is com- 

 posed of carbonate, phosphate, 

 and rluate of lime, and of car- 

 bonate and phosphate of mag- 

 nesia, deposited in a cartila- 

 ginous or other matrix ; whilst 

 the soft consists of that matrix, 

 and of the periosteum which 

 invests the outer surface of 



i-ig. 346-TAe same, viewed under a ^ ^ d £ fa Q me( l u H ar y 



lower power, appear to be a series u "^ " > . m •• • 



of small black dots. membrane which lines its in- 



terior or medullary cavity, and 

 is continued into the minutest 

 pores. If we take for exami- 

 nation a long bone of one of 

 the extremities of the human 

 subject, or of any mammalian 

 animal, we shall find that the 

 bony substance, or shaft, is 

 slightly porous, or rather oc- 

 cupied, both on its external 

 and internal surfaces, by a 

 series of very minute canals, 

 which, from their having been 

 first described by our coun- 

 tryman Clopton Havers, are 



termed to this day the Haver- 

 Fig. 347. A transverse section of the . . j «,„-■«» -P,™ flia 



Hum me, or fore-arm bone, of a sian canals, and serve lor tne 

 Tvrt (CheUmia mydas). it ex- transmission of blood- vessels 



hibit t aces of Haversian canals, . . „ , , 



witii slight tendency to a con- into the interior or tne none. 



c nt arrangement of bone-cells , ,- ___, tViin +r»T»<svprc;f» sor- 

 arou them The bone-cells are U 110 W a tUin transverse sec 



large mi very numerous, but rion of the same bone be made, 



occur r I he most part in parallel . . • i *__ + i • rtTV _. 



rows. and be examined by the micro- 



