TISSUE NOT DEPOSITED FROM BLOOD. 



99 



and the conditions under which these cease to be manifested, 

 rather than upon the presence of particular substances in 

 the papulum itself. Different kinds of germinal matter 

 have power to rearrange the elements of the very same 

 pabulum supplied to them, in different ways, so that one 

 kind of germinal matter produces muscle, another nerve, 

 another fibrous tissue, and so on ; each of these tissues, 

 and, of course, the pabulum itself, containing oxygen, 

 hydrogen, nitrogen, carbon, and some other elements, but 

 differently combined and differently arranged. 



Athough the opinion is still entertained by many ana- 

 tomists that tissue as, for example, the intercellular sub 

 stance of cartilage is deposited directly from the blood, no 

 one has explained by what means the composition of the 

 pabulum becomes so changed as it passes through the 

 walls of the vessels to be distributed between the masses 

 of germinal matter. On the other hand, the facts ad- 

 vanced by me several years ago in favour of the view that 

 every kind of formed material passes through the state or 

 stage of germinal matter have not been overthrown. The 

 existence of germinal matter before the production of the 

 formed material of cartilage and all other tissues ; the con- 

 tinuity of the germinal matter with the formed material in 

 tissues in process of development ; the circumstance of no 

 case being known in which formed material is produced 

 without germinal matter ; and the demonstration that fluids 

 will pass through a comparatively thick layer of formed 

 material, and reach the germinal matter in the course of a 

 few seconds, have forced upon me the conviction that 

 pabulum invariably passes to the germinal matter, and some 



H 2 



