LECTURE IV. 



own, which separate them from the intermediate sub- 

 stance. For by the help of chemical reagents (concen 

 trated mineral acids, and particularly hydrochloric acid) 

 we are enabled, by dissolving the basis-substance, 

 namely, to disengage the corpuscles from it. In this way 

 we furnish, I think, the most complete demonstration 

 that they are really independent structures. Besides, a 

 nucleus may be distinguished within these bodies ; and, 

 even without entering into the history of their develop- 

 ment, we discover that here too we have once more to 

 deal with cellular elements of a stellate form. Bone 

 therefore exhibits in its composition a tissue, containing, 

 in an apparently altogether homogeneous basis-substance, 

 peculiar, stellate bone-cells distributed in a very regular 

 manner. 



The intervals which exist between every two of the 

 vessels in bone are often very considerable ; whole sys- 

 tems of lamellae, beset with numerous bone-corpuscles, 

 thrust themselves in between the medullary canal. Here 

 it is certainly difficult to conceive the nutrition of so 

 complicated an apparatus to depend upon the action of 

 vessels some of them so remote, and especially so, to un- 

 derstand how every individual particle of this extensive 

 compound mass can manage to maintain a special rela- 

 tion of nutrition to the vessels. For experience shows 

 us that every single bone-corpuscle really possesses con- 

 ditions of nutrition peculiar to itself. 



I have laid these details before you, in order to point 

 out to you the gradual transition which takes place from 

 the vascular and abundantly vascular, to the scantily 

 vascular and non-vascular parts. If we would form a 

 simple conception of the conditions of nutrition, I think 

 we must lay it down as a logical principle, that what- 

 ever is enunciated with regard to the nutrition of very 

 vascular parts, must also hold good for that of scantily 



