Cytology and Movements of the CyanophycecB. 295 



tation of the other constituents, and it may be well to men- 

 tion some of these. By micro-chemical methods it is found 

 that glycogen occurs constantly in the cells of the Cyano- 

 phycecx as claimed by Errera (24), and is probably the 

 form in which much of the food is found. The granules 

 and vesicles of the central body give evident reactions for 

 iron and phosphorus. The vesicles are not dissolved by 

 gastric digestion, but take a strong yellowish hue, like the 

 nuclei of Spirogyra filaments when placed in the same fluids 

 with the Cyanophycec^. Tryptic digestion also fails to 

 dissolve the central body, as does 10 per cent, potassium 

 hydrate solution. The central body gives faint tests for 

 plastin. Neither bichloride of potassium nor iron reveals 

 tannin. In cells that have ceased to multiply, osmic acid 

 reveals oil droplets in the outer protoplasmic zone. It will 

 be seen, therefore, that these and other micro-chemical 

 results that have been mentioned above, give strong con- 

 firmatory proofs of the conclusions here drawn. 



(3) Morphology of the Dividing Cell. 



The resting stage of the cell differs greatly from the 

 dividing condition of the same cell. In the former it has 

 been shown that the chromatin is aggregated into a number 

 of hollow vesicles. As the cell begins to divide, these vesi- 

 cles give up their chromatin which becomes very diffuse 

 throughout the central body (Fig. 6), gradually forming 

 into a more or less loose network (Figs. 2, 16, 67). This 

 network is composed of faintly staining threads along 

 which, and especially at the points of juncture of one thread 

 with another, small chromatin granules are situated (Figs. 

 2, 16). These chromatin granules multiply by divisions 

 that are transverse to the axis of the thread (Fig. 23). This 

 division is not the longitudinal splitting found m the 

 spiremes of higher cells for the purpose of equally dividing 

 the probable hereditary material, but is apparently merely 



