714 



THE MICROSCOPE. 



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 hard and 

 soft part ; the hard is com- 

 posed of carbonate, phosphate, 

 and fluate 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 



Fig. 346 The same, viewed under a fu_ -L. nr > Q nrl nf fhp mpdnllnrv 

 lower power, appear to be a series ttie bone > ancl I tne meCLUllary 



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 oj the . , -, ,-, 



Humerus, or fore-arm bone, of a sian canals, and serve for the 

 SSt^SS^S^ "nals," transmission of blood-vessels 

 with a slight tendency to a con- into the interior of the bone. 



centric arrangement of bone-cells Jf .1 - f T . aT , a , 7 p,op QPP 



around them. The bone-cells are " now a tmn transverse 



large and very numerous, but fcion of the same bone be made, 



occur for the most part in parallel . . , -, , -, 



rows. and be examined by the micro- 



