282 Phillips on a Comparative Study of the 



pores on the sides where ciHa pass through. The same is 

 true of Cylindrospermum and such other forms as possess 

 these organs. They are best seen after corrosion with iodine 

 and sulphuric acid (Figs. 27 and 67,) when the wall becomes 

 swollen and the pores become more evident. In the cells 

 figured, the sulphuric acid has so plasmolized the protoplast 

 as to cause it to withdraw the protoplasmic processes from 

 the pores, leaving them empty and distinct, while the proto- 

 plasmic fingers which passed through them are shown pro- 

 jecting from the protoplast. In cross sections made with the 

 microtome, these pores are quite evident, especially if the 

 organism has been cultivated for a few days in a dilute 

 solution of palladious chloride. 



The Central Body. 



The protoplast of the Cyanophycean cell is definitely 

 divided into two portions, the central body and the outer 

 protoplasmic zone. This distinction can usually be deter- 

 mined in the living cell. The central body in living material 

 is generally quite colorless and filled with large grains or 

 "slime balls" as they have been termed by some investi- 

 gators. These balls may be so large as to give the appear- 

 ance of a fragmented central body (Fig. 37). From their 

 position and reaction, these are evidently what Biitschli (9) 

 termed the "red granules," on account of their staining 

 a reddish blue with Delafield's hsematoxylin. Biitschli con- 

 sidered them to be composed of chromatin. Palla and Stock- 

 meyer could not find them within the central body, but upon 

 the outside of it, the reactions were such, however, as to lead 

 them to conclude that they were composed of chromatin. 

 When colored by the ordinary nuclear staining methods and 

 stains, they are shown to have a periphery composed of a sub- 

 stance reacting exactly like chromatin, while the central part 

 does not seem to take up the stain at all or very slightly. The 

 central body therefore appears as if composed of a number 



