Cytology and Movements of the Cyanophycew. 249 



a colorless foundation-mass. In 1900 Zacharias again pub- 

 lished the results of an investigation of much moment. In 

 it he discussed at some length the staining theories of 

 Fischer in a manner that brought out many interesting 

 points. In fact Zacharias has published several (92, 93) 

 very able articles on methods of cytological investigation 

 which have been of great value in the present inquiry. His 

 conclusions were that while there were restrictions to be 

 held in mind, still it was quite admissible to use staining 

 reactions in determining the cell and nuclear constituents. 

 In this work, Zacharias, in discussing at great length the cell 

 contents of the Cyanophyceae, concluded that "from the 

 present state of our knowledge we can say in regard to the 

 arrangement of the colored and colorless contents of the 

 cell, that a colorless central body is surrounded by a colored 

 plasma. The latter may be lacking under certain condi- 

 tions," but as there was no bounding membrane, he would 

 not call the colored portion a chromatophore. The central 

 body was a very irregular, structureless and compact mass, 

 enclosing larger or smaller colorless spaces. Its contents 

 showed great varieties of condition, even in the same species. 

 He said, "As many different species of Lyngbya as are in 

 the palm house at Hamburg, each one showed a different 

 arrangement in the cell rows." The same species also dif- 

 fered at different times of the year. The granular constitu- 

 ents he considered to be of two kinds, the cyanophycin 

 granules in the peripheral plasma, and the colorless central 

 granules embedded in the periphery of the central body, 

 which corresponded to Palla's slime balls, though he did not 

 use that term on account of the different meanings given to 

 it by different authors. He considered it quite possible 

 that his "central granules" were composed of chromatin 

 though he was unable to demonstrate it to his satisfaction. 

 When treated with 28 per cent, hydrochloric acid they had 

 the appearance of hollow balls. They occurred most abun- 

 dantly in the spores and not at all in the heterocysts. It was 



