1898-99. ] ON THE CYTOLOGY OF NON-NUCLEATED ORGANISMS. 443 
of Zolypothrix after treatment with a digestive fluid, and extraction with 
alcohol and ether, and on examination in a solution of hydrochloric acid 
of 0.3 per cent. strength. In this case the nucleus was demonstrated by 
the nuclein lustre produced. The nuclein was extracted with a soda 
solution of 0.05 per cent. strength from threads which had previously 
been submitted to digestion. He found also in a species cf Oscillaria, 
after treatment with digestive fluids, a large nucleus, containing nuclein 
network, in every cell. From such preparations the nuclein was removed 
by extraction with very dilute soda solutions. 
Scott’ has described the occurrence of nuclei and nuclear division in 
Oscillaria and Tolypothrix. The nuclei were rounded, sometimes con- 
tracted. and presenting evidences of a fibrillar structure like that ob- 
served in the “skein” stage of the nuclei of more highly specialized 
cells. Scott regarded this structure as due to the division of the nucleus, 
‘as it was accompanied by division of the cell as a whole, and he found 
in a few preparations indications of colourless striz connecting the por- 
tions of the nuclear structure, and suggesting the idea of “achromatin 
fibres.” In some cells the nuclear fibrilla were broken up into smaller 
portions which resembled the chromatin segments of division in ordi- 
nary cells. 
A second publication’ by Zacharias contained the results of a very 
comprehensive research on the structure and micro-chemistry of the 
cells of the Cyanophyceze. He found in all the forms examined by him 
that only the peripheral portion of the cell substance is coloured, the 
central portion appearing colourless. The coloured substance was more 
abundantly present on the lateral than on the transverse walls. He was 
unable to determine the existence of a chromatophore. Vacuoles were 
not present in the normai cells, but made their appearance in threads 
which were observed dying under the microscope. In Osellarza, after 
several days’ culture, with the exclusion of light, vacuoles of an. unde- 
termined character were found to occur. In the colourless central por- 
tion of the cells articulated or granulated structures, with one or two 
bodies which possessed the appearance of nucleoli, could be recognized 
in favourable cases. The nucleoli-like elements were colourless, spherical, 
not sharply circumscribed, and appeared as if their peripheral substance 
was of a denser consistency than their centre. A portion of the central 
body of the cell was found to be soluble in artificial gastric juice, the 
undissolved residue being composed of two substances, or of one only. 
t. “On Nuclei in Oscillaria and Tolypothrix,” The Journal of the Linnean Society, Botany, 1887, 
Vol. XXIV, p. 188, 
2 ‘*Ueber die Zellen der Cyanophyceen,”’ Bot. Zeitung, 1890, Nos. 1-5. 
