OF CELL- WALL OF FUNGUS. 



197 



the capsule is thickened the new material is deposited from 

 the matter lying within, upon the inner instead of upon the 

 outer surface of the envelope. The matter deposited upon 

 the inner surface of the capsule is always softer than its 

 general substance, and the external surface of old capsules 

 which passed long ago from the state of bioplasm into that 

 of formed material, is cracked and ragged. PI. I, fig. i,f. 

 In many of the algae this external surface is so cracked 

 and rough, that it serves as a nidus for the development and 

 growth of smaller algae and other organisms a fact which 

 clearly shows that the matter has ceased to be active, is 

 undergoing disintegration, and is becoming fitted for the 

 pabulum of other things. It is no longer firm nor capable 

 of resisting the action of external conditions. This is clearly 

 the oldest part of the capsule which is now undergoing 

 decay, and the small algae are living in part upon the pro- 

 ducts which result. The new material is in many cases 

 added upon the inner surface of the capsule, layer after 

 layer, and where there are several layers the innermost is 

 the youngest and the outermost the oldest portion of the 

 structure. These several layers sometimes separate slightly 

 from one another. In nutrition then, the inanimate material 

 to be appropriated and applied for the nourishment of these 

 structures must pass through the outer membrane, and be 

 taken up by the living matter within. Here are com- 

 municated to it, in a manner we do not understand, the 

 same properties and powers which the already existing living 

 matter itself possesses, and which it has inherited from pre- 

 existing particles. The' nutrition of cells of epithelium and 

 other bioplasts of man is conducted upon the same plan. 

 See p. 220. At present observation does not carry us further 



