Cytology and Movements of the Cyanophycece. 241 



Such conflicting evidence is the result, it would seem, of 

 two factors : first, the want of any uniform meaning for the 

 word "nucleus" among the different observers; and second, 

 the failure to recognize that the nucleus and other cell con- 

 tents may give different reactions with the same reagent at 

 different times. This latter fact has been abundantly shown 

 by the nuclei of higher organisms during division and other 

 life phases, where varying concentrations and modifications 

 of the nucleic acid (52) may occur. Why the same variabil- 

 ity should, among the nuclei of the lower forms, be taken 

 as indicating a different morphological structure is hard to 

 conceive. The fact that protoplasm itself is a mixture of 

 various complex bodies, which through metabolism and 

 growth are continually changing, would leave no valid 

 reason for considering that variations in the cell contents, 

 even as profound as those of the "central body" of the 

 Cyanophycean cell should not exist. 



The earlier writings on the cytology of the Cyanophyceae 

 were by Schmitz in 1879. He did his work upon Gloeo- 

 capsa polydermatica, Oscillaria princeps and Anabaena Hos- 

 aquae. In his earlier work (6y), after many attempts, he 

 discovered a homogeneous central body which he consid- 

 ered to be a cell nucleus, though it did not seem to appear 

 in every cell of all preparations. Hsematoxylin showed this 

 nucleus of Oscillaria princeps to be spherical and excentrically 

 placed. He also found the cells to be more or less com- 

 pletely filled with large round granules of unknown com- 

 position, which he called "schleimkugeln." Though he used 

 hsematoxylin to stain his preparations, he was able to make 

 out the structure equally as well without its use. He there- 

 fore discarded the stain and drew his conclusions from the 

 fresh, unaltered material. 



The following year Schmitz (68) again published on the 

 cytology of the Cyanophyceae. Here he retracted his views 

 of the former year, declaring that these plants were non- 

 nucleolated and non-nucleated. The central body, which 



