154 ' THE BEGINNINGS OF LIFE. 



observers, which is found to enter largely into the com- 

 position of many of the tissues of the body, denies that 

 anything to which the ordinary definition of a cell would 

 be applicable can be said to constitute the elementary 

 part of many tissues. He says J : c We may, how- 

 ever, use this term, which is very short and conve- 

 nient, if we give it a more general meaning. I would 

 venture to describe the cell or elementary part as a 

 structure always consisting of matter in two states, 

 forming and formed^ or germinal matter and formed 

 material. The first or active substance is surrounded 

 and protected by the outer passive matter, through 

 which all the pabulum to be converted into ger- 

 minal matter must pass/ Looking therefore upon the 

 central portion (corresponding to nucleus and part 

 of cell contents) as the living part or germinal matter, 

 in which the active powers of grov/th reside, and by 

 the division of which new germinal centres are pro- 

 duced j he regards the peripheral portion (correspond- 

 ing to the outer part of cell contents, the cell-wall and 

 the intercellular substance of most other writers) as dead 

 matter, incapable of undergoing any further changes 

 that may be called vital. The outermost layers of 

 germinal matter are supposed to be continually losing 

 their peculiar powers, and passing into formed mate- 

 rial ; whilst the new materials of growth penetrate to 

 the very centre of the germinal mass, where all the 



1 ' Structure and Growth of Tissues,' ' Journal of Microscopical 

 Science,' 1861, p. 62. 



