110 THE STORY OF LIFE'S MECHANISM. 



ent parts. One portion is apparently identical with 

 the reticulum of the cell substance (Fig. 23, d). 

 This forms an extremely delicate network, whose 

 fibres have chemical relations similar to those of 

 the cell substance. Indeed, sometimes, the fibres 

 of the nucleus may be seen to pass directly into 

 those of the network of the cell substance, and 

 hence they are in all probability identical. This 

 material is called linin, by which name we shall 

 hereafter refer to it. There is, however, in the 

 nucleus another material which forms either 

 threads, or a network, or a mass of granules, 

 which is very different from the linin, and has 

 entirely different properties. This network has 

 the power of absorbing certain kinds of stains 

 very actively, and is consequently deeply stained 

 when treated as the microscopist commonly pre- 

 pares his specimens. For this reason it has been 

 named chromatin (Fig. 23, e), although in more 

 recent times other names have been given to it. 

 Of all parts of the cell this chromatin is the 

 most remarkable. It appears in great variety 

 in different cells, but it always has remarkable 

 physiological properties, as will be noticed pre- 

 sently. All things considered, this chromatin is 

 probably the most remarkable body connected 

 with organic life. 



The nucleii of different animals and plants 

 all show essentially the characteristics just 

 described. They all contain a liquid, a linin 

 network, and a chromatin thread or network, 

 but they differ most remarkably in details, so 

 that the variety among the nucleii is almost 

 endless (Fig. 26). They differ first in their size 



