624 
N. H. SWELLENGREBEL. 
paraffin (52°), and cut in sections from 4 — 6 fi thick. The 
sections were washed in xylol and stained with iron-hema- 
toxylin (Heidenhain). 
I shall not enumerate here the different papei’S which have 
been published about the cytology of Cyanophyceae. For 
reference to them the very complete works of Kohl,^ Fischer,* 
and Guilliermond ® may be consulted. According to Guillier- 
mond, who recently studied various representatives of this 
group, the central mass of stainable matter (the “ central 
body” of Biitschli^) is composed of chromatin which is sup- 
ported by an achromatic substratum of alveolar structure; 
the whole central body is to be regarded as a primordial 
nucleus, a view which was already held by Biitschli and his 
followers. A contrary opinion is upheld by A. Fischer, who 
does not believe in the nuclear nature of the central body ; 
according to this author it represents only the central part of 
the cytoplasma free from chlorophyll. The chromatophil 
bodies within it consist of a peculiar hydrocarbon called “ ana- 
bsenine.” His strongest argument against the chromatic 
nature of those granules consists in the fact that they ai'e 
dissolved in water. It must be remembered, however, that 
this argument no longer holds good, since Oes ® showed that 
the chromosomes of Spirogyra are equally dissolved in water. 
Kohl (loc. cit.) showed that the chromatophil granules of 
the central body give all the characteristic reactions of 
true chromatin. I also have carefully examined the micro- 
chemical reactions of those granules, and have arrived at the 
same conclusion as Kohl’s. I do not describe them here, since 
Kohl has done this in ex ten so. There cannot consequently 
be the least doubt that the granules within the central body 
' Kohl, ‘ tiber der Organisation luid Pliysiologie der Cyanophyceen,’ 
Jena, 1903. 
" Fischer, ‘ Botan. Zeitimg,’ 1905. 
’ Guilliermond, ‘ Revue general de botanique,’ 1907. 
< Biitschli, ‘ fiber die Bander Cyanophyceen und Bacterien,’ Leipzig, 
1826. 
* Oes, ‘ Botan. Zeitimg,’ 1908. 
