WITH THE MICROSCOPE. 321 



matter or cells take no active part in the formation of the matrix. 

 But no one who holds this doctrine has attempted to explain by 

 what means the pabulum becomes altered as it passes through the 

 walls of the vessels and is changed in its composition so as to resemble 

 the existing cartilaginous texture lying in the intervals between the 

 masses of germinal matter. 



It is quite certain that nothing having the composition of cartilage 

 exists already formed in the blood ; and indeed those who teach that 

 the process of nutrition is of the nature above indicated, are driven 

 to attribute mysterious transforming powers either to the lifeless 

 vascular walls, or to the equally lifeless tissue its.elf. It would be as 

 unreasonable to attribute transforming powers to lifeless wood, or 

 glass, or stone, as to fibrous tissue, cartilage, bone, &c. 



It will have been observed that according to my view the 

 changing transforming powers reside in the germinal matter alone. 

 The facts advanced by me in 1861, concerning the nature of the 

 germinal matter have not been overthrown. I have endeavoured to 

 show, not that the germinal matter acts upon matter which passes by 

 it and so changes it without undergoing change itself, but that every 

 kind of formed material and tissue passes through the condition of 

 germinal matter, and that therefore in the formation of fibrous tissue, 

 cartilage, &c., pabulum from the blood is taken up by the germinal 

 matter, becomes germinal matter and in its turn is gradually resolved 

 into the matrix or intercellular substance. 



The existence of germinal matter before the production of formed 

 material ; the continuity 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 com- 

 paratively thick layer of formed material, and reach the germinal matter 

 in the course of a few seconds, forced upon me the conviction that 

 pabulum invariably passes to the germinal matter, and that it, or at 

 least some of its constituents, undergo conversion into this living 

 substance, and acquire its properties and powers, while at the same 

 time other portions of the germinal matter lose their active powers, 

 and undergo conversion into formed material. 



So that pabulum invariably becomes germinal matter, and the 

 germinal matter, not the pabulum, is converted into formed material. 

 I have been accustomed to state these facts as follows : Calling the 

 germinal matter which was derived from pre-existing germinal matter 

 a, the pabulum b, and the formed material resulting from changes in 

 the germinal matter c, I say b becomes a, and a becomes converted 

 into c, but b can never be converted into c except by the agency, 



Y 



