THE NUCLEUS 



39 



it shows the same staining reactions as chromatin, or may be double, 

 consisting of an outer achromatic and an inner chromatic layer. Ac- 

 cording to Reinke, it consists of oxychromatin-granules like those of 

 the linin-network. 



Interesting questions are raised by a comparison of these facts 

 with the conditions observed in some of the lowest organisms, such 

 as the flagellates and lower rhizopods among animals and the 



'. . • •■< 



A 



• ! 



Q 



CX) 

 CO 



E I 



Fig. 16. — Forms of Cyanopliycefe, Bacteria, and Flagellates showing the so-called scattered 

 or distributed nuclei. [.-i-C". BiJTSCHLl ; ZP-/^. SCHEWIAKOKF; G-y. Calkins.] 



A. Oscillaria. B. Chromatiuni. C. Bacterium lineola. D. Achromatium. E. The same in 

 division. F. Fission of the granules. G. Tetramitus, with central sphere and scattered granules. 

 A^. Aggregation of the granules. /. Division of the sphere. J. Fission of the cell. 



H 



Cyanophyceae and Bacteria among plants. In many of these forms 

 (Fig. 16) no distinct nucleus can be demonstrated, the cell consisting 

 of a mass of protoplasm in which are scattered numerous deeply 

 staining granules. Many of these granules stain intensely with 

 hasmatoxylin and other "nuclear" dyes; like chromatin, they resist 

 the action of peptic digestion, and in at least one case (the bacterium- 

 like AcJi7-omatium, according to Schewiakoff, '93) they have the power 

 of division like the chromatin-granules of higher forms. For these 



