in Plant Cytology. 187 



continuous Avith enclosed nuclear chromatin. The existence 

 of such a network has since been demonstrated in a variety 

 of species, and in many instances the threads of it link 

 together the plastids where such occur. From its bright 

 refractive appearance, its evident continuity with the nuclear 

 membrane, and its behavior to fixatives, to corroding agents 

 and to chromatin stains, I would regard it as an extremly fine 

 network, built up of linin and chromatin constituents, con- 

 tinuous with similar constituents of the nucleus. 



But with Gardiner's work on intercellular protoplasmic con- 

 tinuity before us, an important though possibly difficult line of 

 inquiry will be to ascertain whether the continuity be one of 

 the general vegetative protoplasm only, or whether there does 

 not exist an intercellular network of linin-chromatin fibres. 

 In dividing cells of banana root, bean root, polygonum stem, 

 etc., we can at times see in adjacent cells that are dividing, 

 strands of a denser substance than the protoplasm, which 

 appear to be continuous as longitudinal striae from spindle 

 pole to spindle pole. May we not therefore have an intercel- 

 lular linin-chromatin network which may link together not 

 merely the protoplasmic, but the hereditary substance ? 

 Townsend's researches on the apparent intimate relation 

 between nucleus and cell wall suggest such a condition, while 

 the wave-like rhythm of division-activity which traverses 

 most filaments of Spirogyra during division, suggest similar 

 relations. A careful study of the latter plant has given as yet 

 only negative results. 



Before considering the nucleus it may be pertinent to 

 inquire as to the value to be placed on differential stains, and 

 specially the erythrophil and cyanophil reactions. Since the 

 studies by Schwartz and Rosen, so many conflicting views 

 have been advanced that Miss Huie's observations on Droscra 

 were specially welcome. Wager's observations on hymeno- 

 mycetous cells prepare us to believe that the relative stain- 



