Cytology and Movements of the Cyanophycee. 243 
A criticism on the work of both Schmitz and Wille is 
that they used only one stain, hematoxylin, and in part of 
his experiments, Schmitz used only fresh material. The 
use of fresh, unchanged material is of course preferable if 
supported by other observations, but confirmatory tests are 
quite essential. Observational results without such safe- 
guards are never conclusive though Wille’s descriptions 
seem very accurate. His conclusions would have carried 
much greater weight if he had left figures illustrative of 
what he saw. 
Tangl (78) was unable to find a nucleus, but this was 
probably due to poor methods. He described an Oscillarian 
organism, Plaxonema oscillaris, which had a rod-shaped 
chromatophore. However, as Molisch (55) showed phy- 
cocyanin to be a crystalline substance, Gomont (32) con- 
sidered this chromatophore to be merely a crystallization of 
that pigment. Tangl described zoogloez which appeared 
on culturing Plaxonema as follows: “The filaments first lose 
their power of motion, coming to a standstill after the fol- 
lowing changes, which are of two kinds (@) the filaments 
either separate into single cells, or (0) in certain places there 
arise small zoogloee which enclose a changing number of 
shorter or longer parts of filaments. . . . The plasma of 
the filaments assumes a finely granular appearance, the glit- 
tering granules on the partition walls alone remaining of the 
earlier contained bodies, the chromatophore becomes loos- 
ened and withdraws from the walls.” From this descrip- 
tion it seems hardly probable that the organisms were in a 
good state of preservation, and his conclusions for that 
reason scarcely bear upon the morphology of the Cyano- 
phycez. 
Borzi (6) worked on Nostoc, Anabaena, Oscillaria, Sper- 
mosira, Cylindrospermum and Sphaerozyga, and endeav- 
ored to determine intercellular protoplasmic continuity pri- 
marily, but his conclusions in other lines are as interesting, 
or more so, than in the line that he started to investigate. 
