714 



THE MICROSCOPE. 



of small Hack dots. 



Professor Quckett's paper, Micros. Soc. Transactions, 

 furnishes the earliest reliable 

 information on the " In- 

 timate structure of Bone." To 

 this paper we are indebted 

 for the following microscopica' 

 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 

 the bone, and of the medullary 

 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 tM . -. , ^ /. , , 



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



Turtle (Chelonia mydas). It ex- trfT>jrm<?<?ioTi of blood -VPSSels 

 hibits traces of Haversian canals, transmission ( 



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

 If now a thin transverse sec- 



, 



and be examined by the micro- 



