ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 455 
Coccus-Condition of Beggiatoa.* — Herr W. Zopf has been able to 
determine the passage of the very fine peach-red filaments of Beggiatoa 
to a swarming coccus-condition, which he regards as a process of retro- 
gression ; but the progressive development of these to the filament- 
condition was not demonstrated. The shortly elliptical coccoid elements 
still contained grains of sulphur, which were always formed in pairs in 
each element. 
New Pathogenous Micrococci.f — In specimens of special varieties 
of potato having a disagreeable smell M. E. Koze finds two new species 
of Micrococcus , which he names M. nuclei and M. imperator. The former 
consists of oval-elliptical cells with a diameter 0*5 by 0 * 33 yu, ; the 
latter of cells of a similar form 1 by 2 fx in diameter. 
Mucogenous Bacteria.J — In an article on the developmental history 
of the mucogenous bacteria, Herr H. Behrens remarks that these slimy 
masses have been known from the earliest times as affecting wine, 
milk, beer, and other vegetable products. Glceogenous bacteria will even 
thrive in distilled water, and their settlement in the laboratory of the 
pharmacist or chemist is most detrimental, as they are only eradicated 
with great difficulty. In some places, however, as in Norway, muco- 
genous bacteria are used in the preparation of an edible called Wai, 
which is milk rendered jelly-like, from which all the casein has dis- 
appeared. In Ireland and other places mucogenous bacteria are used 
for making cheese. On the whole, however, the presence of these bac- 
teria, especially in milk, is harmful, and the sale of infected substances 
is properly forbidden. When cultivated on gelatin the colony is 
colourless or cream coloured, and looks like a crumb of bread. The 
eonviction is arrived at, from carefully considering their growth, that 
these bacteria derive much of their nutriment directly from the air. 
When cultivated in bouillon the mucous alteration is effected in a few 
days, the whole being converted into a jelly-like mass entangling gas- 
bubbles. 
The gummy mucus is of at least two kinds ; one being perfectly 
soluble in water, the other merely swelling up. One stains yellow with 
<;hloriodide of zinc, the other disappears on the addition of this reagent. 
Deposits occur with the ordinary precipitants, such as alcohol, alum, 
acetate of lead, and also with the special reagents for albumen. Micro- 
scopical examination of fresh material shows a bacterium within a 
mucous cell ; but in stained film preparations the mucous cell disappears, 
and only the ordinary appearance of a bacterium is visible. By placing 
a fresh piece of mucus on a cover-glass and staining with Weigel’s 
hsematoxylin solution, treating with acid alcohol and contrast-staining 
with fuchsin, the mucous cells come out perfectly, the mucous sheath 
being pale blue and the bacterial cell red. At the same time the extra- 
ordinary polymorphism of these organisms appears ; cocci of various 
.arrangement, bacilli and filaments are all present. On potato the 
growth is characteristic ; along the inoculation track long worm-like 
deposits of different colours develope. 
* Beitr. z. Phys. u. Morph, niederer Organismen (Zopf), i. (1895) pp. 37-44 (2 figs.). 
t Comptes Rendus, cxxii. (1896) pp. 543-5. 
X Zeitschr. f. angewandte Mikr., ii. (1896) pp. 4-9. 
2 i 2 
