222 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Protophyta. 
a. Schizophyceae. 
Genetic Connection of Scytonema, Nostoc, and Gloeocapsa.* — 
Herr H. Zukal describes the result of experiments made chiefly on 
Scytonema myocJirous, in order to ascertain its power of assuming other 
forms. For this purpose the Scytonema-Maments were placed in the 
axils of moss-leaves grown in pots. In about three weeks a change 
commenced, the sheath swelled up and became more transparent, and 
the filament gradually assumed a blue-green colour, and was divided 
repeatedly by very fine septa. The cells now assumed a more rounded 
form, and, the filament growing much faster than its inclosing sheath, 
became necessarily twisted and coiled in a variety of ways. Hetero- 
cysts and hormogones were also gradually formed, and the separate 
portions of the filament became inclosed in a very thin internal 
secondary sheath. The Scytonema had now assumed all the characters 
of Nostoc rujpestre or microscopicum, except that it consisted of only a 
single filament, and that the outer sheath took no part in its curvature. 
When cultivated in a nutrient solution, this N ostoc-iovva continued to 
reproduce itself ; while, if grown in distilled water, it had a tendency to 
reassume a Scytonema-condaiioTi. Continued cultivation on moss leaves 
induced still further degeneration, and the iVbs^oc-filament gradually 
broke up into separate cells, each invested with its own mucilaginous 
sheath, in which condition it is a Gloeocapsa, closely resembling 
G. seruginosa ; and this again, by further culture, became a Chroococcus, 
with very thick sheath. 
Parasitism of Nostoc on Gnnnera.j — According to Herr P. Merker, 
the filaments of Nostoc enter the leaves of Gunnera macropJiylla through 
the mucilage-canals in the glands, where they first take possession of the 
empty space caused by the conversion into mucilage of individual gland- 
cells. From here filaments find their way into the intercellular spaces 
of the starchy parenchyme which surrounds the glands. When a Nostoc- 
filament enters a cell of this tissue, it applies itself closely to the cell- 
wall, dissolves it or converts it into mucilage, advances to the interior 
of the cell, consumes the whole of the starch, and completely fills up 
the cell. Individual filaments then attack neighbouring intercellular 
spaces, and the contents of other cells are consumed in the same way. 
/3. Schizomycetes. 
Transformations of Microbes.^ — M. A. Chauveau has continued his 
researches on the limits, conditions, and consequences of the variability 
of Bacillus anthracis ; and now describes those in which he has tested 
the ascending or reconstituting variability of this form. He finds that 
the Bacillus anthracis may exhibit three types, the respective properties 
of which appear to have been definitely acquired. 
(1) The bacillus brought to the bottom of the scale of descending 
variation, non-virulent, but still with vaccinal properties. 
(2) The bacillus partially revivified by ascending variation and 
* Oester. Bot. Zeitschr., xxxix. (1889) pp. 349-54, 390-5, 432-5 (1 pi ). 
t Flora, Ixxii. (1889) pp. 211-32 (1 pi.). 
X Comptes Rendus, cix. (1889) pp. 597-603. Cf. this Journal, 1889, p. 796. 
