Notes . 
5i3 
ON" A NUCLEAR- STRUCTURE IN THE BACTERIA 1 . — Owing 
to the small size of the cells in the Bacteria, the presence of a nucleus, 
or of anything akin to a nucleus or nuclear structure, has not yet 
been satisfactorily demonstrated in them. Dr. P. Ernst has, however, 
described certain bodies which to him appeared to be of the nature of 
nuclei, inasmuch as when treated with reagents they give a reaction 
different from that observed in spores. 
It is interesting to note that, in the closely allied group of the 
Cyanophyceae, Scott and Zacharias have been able to detect a structure 
resembling a nucleus. Zacharias has, however, recently shown that 
these nuclear bodies possess very little nuclein, and he is in conse- 
quence not inclined to regard them as nuclei. 
According to Butschli, the central portion of the protoplasmic 
contents of the Bacterium-cell is to be regarded as of the nature of a 
nucleus in that it very readily takes up certain aniline dyes. It should 
be noted, however, that such stains as haematoxylin, carmin, safranin, 
&c., have but little staining power for the contents of the Bacterium- 
cell, compared with such stains as gentian, violet, fuchsin, &c., which 
stain them deeply, but which also stain the protoplasm of the cells of 
higher plants almost as deeply as the contents of the Bacterium-cell. 
This seems to show that the Bacteria contain very little of the 
chromatic substance which is found in the nuclei of the higher plants. 
The author of this paper has, for some time, been working at the 
Bacteria in the hope of elucidating this point, and has obtained a 
Bacillus in which a distinct nuclear structure can be observed. 
The Bacillus referred to forms a thin scum on the surface of water 
containing Spirogyra in a state of decay. The cells of this organism 
consist of short rods which occur either singly or in pairs. They are 
about 2-5 to 3 ju. in length and from 1-3 to 1*5 \i in diameter, and 
when seen in a fresh state one or more highly refractive granules can 
be observed in each cell. In cover-glass preparations stained with 
fuchsin, all stages in the division of the Bacillus could be observed. 
The preparation should be made during the earlier stages of the 
development of the scum on the surface of the water, while the bacillus 
is in a healthy growing state. 
In the centre of each cell a substance, deeply stained by the 
fuchsin, is found. This in young cells consists of two rods, deeply 
stained, placed side by side, with a less deeply stained substance 
1 Abstract of paper read at the meeting of the British Association, August, 1891, 
