THE STUDY OF THE 



17 



Fig. 9. 



the linnu To-radial articulation grows fastest ; while in tlic al>dominal limit, 



the extremity most distant from the femoro-tibiul articulation grows tin; least. 



rnin^ the gro\\th nf the h.iiies in thickness, this occurs by the ossifi- 



i of the deep layer of the periosteum called the osteogenetic layer. The 



: inionts of the above-named authors have irrefutably demonstrated this 



tact. The formation of b..ny tissue in the deep layer of the periosteum is very 



active during the youth of animals; but it soon slackens, and in advanced 



- completely. In the first period of life, in proportion as the now 



8 are added to the surface of the bone, the old layers, those nearest the 



me lullary canal, disappear by resorption. Later, the process of res'trption 



<ls that of formation, which is, in old age, completely annihilated. It 



has also been observed that the formation of a certain quantity of the 



osseous elements takes place on the inner face of the medullary canal, at the 



expense of the medullary tissue. In the flat bones, the primitive centre of 



ation is developed nearly in the middle, and the calcareous salts are 



afterwards deposit-d in radiating lines from this spot towards the periphery. 



These bones are augmented in thickness by the formation of subperiostic 



layers, and by the development of the spongy tissue between their two 



compact laminae; they increase in width by the ossification of what arc 



termed the iiniri/iiinl t pijthyaes. 



The short bones grow from the periosteum 

 and the epiphysery cartilages, when they possess 

 complementary centres. 



Xntrifloii. The experiments which consisted 

 in feeding young animals with madder, and 

 afterwards examining their osseous system, have 

 for a long period demonstrated the nutrition of 

 1 tones. When bones cease to grow, their nutri- 

 tion becomes less active ; but it is evident that 

 it does go on, in order to maintain the organic 

 matter of the ossejus tissue in a proper con- 

 dition. 



(Professor Owen has explicitly and concisely 

 stated the development of bone to occur as fol- 

 lows : " The primitive basis, or ' blastema ' of 

 bone is a transparent glairy matter containing 

 numerous minute corpuscles. It progressively 

 acquires increased firmness ; sometimes assuming 

 a membranous or ligamentous state, usually a 

 gristly consistence, before its conversion into 

 It 'lie. The change into cartilage is noted by 

 the appearance of minute nucleated cells, which 

 increase in number and size, and are aggregated 

 in rows, with intercellular tracts, where the 



'ation is about to begin, as in lig. '.'. 



These rows, in the cartilaginous basis of 

 long bniies. are vertical to its ends; in that of 

 flat b mi s they are vertical to the margin. The 

 c- 11> furthest from the seat of ossification are 

 flattened and in close contact ; nearest that seat 

 they become enlarged and separated. 



The first app' i' bone is that of minute granules in the inter- 



columnar and intercellular tissue. Canals are next formed in the bone by 



o 



AI 1111: MAX "i 

 A 1 1"\, .showing at it> 

 lowor ]x>rtius tin- -lu>tiTs 

 <>f cfll.-, .-irran^cil in rulimiiis, 

 ;u h <>(' which is iiicln.soil in a 

 i-h.-ath of ralciiicil intercellular 



