ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
241 
dissolved in the cell-sap. The grana — granules or crystalloids of cyano- 
phycin — are apparently only of one kind, presenting uniform chemical 
and physical characters. 
Herr E. Zacharias,* * * § replying to the observations of Hieronymus, 
asserts that he has not, at present, been able to detect in the Cyano- 
phycet© chromatophores surrounded by protoplasm. The protoplasm 
with green punctations does not appear to be surrounded by a colour- 
less layer of protoplasm specially differentiated and in contact with the 
cell- wall. 
Prof. R. Chodat and Madame O. Malinesco f find, in the protoplasm 
of the CyanophycesB, only one kind of refringent corpuscle. These vary 
in number and size according to age and other circumstances ; but they 
all exhibit the same chemical reactions, being stained by aluminated 
hcematoxylin, vesuvin, nigrosin, saffranin (imperfectly), acetic methyl- 
green, and gentian-violet, and are then decolorized by alcohol. They 
are not the result of the breaking up of a central nucleus, they take no 
part in cell-division, they do not correspond to the chromatin of the 
nucleus of higher plants, and their identity with the corpuscles of 
Biitschli has not been established. 
Oscillatoriacese.J — Prof. A.Hansgirg criticizes Gomont’s monograph 
of the Oscillatoriaceae in several points, especially in that he has in some 
instances united under the same species forms which are essentially 
different, while in others he has separated forms which are but stages of 
development of the same species. 
Phormidium.§ — M. M. Gomont calls attention to the fact that in 
some species of Phormidium the thallus has a more or less complicated 
ramification, as e. g. in P. tinctorium, fasciculatum , and uncinatum. The 
plant which has been described as Calothrix putida is a branched variety 
of P. Retzii, and is identical with P. fasciculatum. Under the name 
P. penicillatum the author describes another new marine species from 
the island of Reunion, in which the thallus is also branched, the upper 
portion of the fascicles being cemented together by a firm gelatinous 
sheath. 
£. Schizomycetes. 
Action of Light on Bacteria. || — Prof. H. Marshall Ward has pub- 
lished an abstract of his third memoir on this subject. He has succeeded 
in obtaining photographic records by throwing the spectrum on an agar 
film evenly charged with the spores and bacilli to be investigated, and 
has observed the behaviour of the illuminated regions after incubation. 
Broadly speaking, the action begins at the blue end of the green, rises 
to a maximum as we pass to the violet end of the blue, and diminishes 
as the ultra-violet regions are reached ; the bactericidal effect, however, 
extends far into the ultra-violet. 
The results suggest that the naked arc-light may prove to be a very 
efficient disinfecting agent in places where the rays can be projected 
* Bot. Ztg., li. (1893) 2^ Abtheil., pp. 225-9. 
t Arch. Sci Phys. et Nat., xxix. (1893) pp. 108-10. 
: Bot. Centralbl., lv. (1893) pp. 72-6. Of. this Journal, 1893, p. 514. 
§ Bull. Soc. Bot. France, xl. (1893) Sess. Extraord., pp. lxxxvi.-xc. (1 pi.). 
l| Proc. Roy. Soc. Lond., liv. (1894) pp. 472-5 (2 figs.). 
