714 



THE MICROSCOPE. 



.%'! WASH XwiS^A 



;'!V iV ,' 'gC .^S^---i- >,{'-' •',/,(», '''..' : '- 



Fig. 346- 

 lower ■power, 

 of small black dots, 



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, 

 fluate of lime, and of car- 

 bonate and phosphate of mag- 

 deposited in a cartila- 

 ginous or other matrix ; whilst 

 the soft consists of that matrix, 



r^^'^Mii^?^'0%M fnd of the periosteum which 

 ^v^v^%^ invests the outer surface of 



S^rTte ?£* 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- 

 m. l bo ne, OJ o/'a sian canals, and serve for the 



Turtle (Chelonia mydas). It ex- transmission of blood-vessels 

 hibits traces of Haversian canals, . . „ , , 



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



centric arrangement of bone-cells jp +>n"n +rcmcvpr<5P <5PP- 



around them The bone-cells are It now a tnm transverse sec- 



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

 occur for the most part in parallel , , • „a v,, +t,„ ™,'„™ 



rowa, and be examined by the micro- 



Fig. 347.— A transverse section of the 



