132 Causes and Course of Organic Evolution 



As to tlie more immediate chemical composition of cell 

 nuclei and associated structures, these are now usually regarded 

 as composed of three complex organic bodies, plastin, nuclein, 

 and chromatin. Of these plastin seems most nearly if not 

 exactly to resemble protoplasm, and would be explained as 

 the nucleoplasm that surrounds the most complex constituents 

 and that nourishes them. Nuclein seems to be an intermediate 

 substance between it and chromatin, while the last-named is 

 the most complex in organization or composition. So on the 

 above view the nuclear plastin is the vegeta1:ive constituent, 

 that is, the absorptive and feeding part of each nucleus or of 

 each plastid ; the nuclein is a product which is gradually passing 

 from a plastin state to the still higher condition of chromatin, 

 and so acts as an intermediary in the linking up or condensation 

 of it; while the chromatin is molecularly the most complex 

 and physically the most highly energized of the three con- 

 stituents. 



Such a view also is favored by staining results like those 

 described by Miss Huie, specially when one compares these 

 with the staining of cells in the resting stage. For, during 

 the latter stage in plant cells, the nucleolus, the radiating 

 nuclear threads, as well as the nuclear membrane that are all 

 richly chromatin-bearing, stain, by use of saffranin and gentian 

 violet, a deep brown-red; various constituents within or along- 

 side these stain of a reddish-purple; while the more liquid and 

 bathing constituent stains of a purplish-blue color. The 

 variations in staining observed by Miss Huie point to a sharper 

 and more active temporary and visible differentiation in the 

 three constituents connected with the more active substance- 

 transformations proceeding during division. 



A marked sensitivity then to environal stimuli, and the 

 capacity to link up the action of several of these stimuli, so 

 as to form a resultant jjroenvironal response, we would regard 

 as fundamental ])ecu]iarities of chromatin or the cognitic sub- 

 stance. 15 ut it may now reasonably be objected that, even 

 if we do not regard chemic or electric energy as sufficient for 

 such resi)onse, biotic energy of the protoj)lasm might amply 



