672 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
other layers, the arrangement of the granules in which recalls the claters 
of the Hepaticse. The cliromatophore is also spiral, having sometimes 
the form of a figure of 8, while it is sometimes twisted like the chloro- 
phyll-bands of Spirogyra. Each chromatophore contains a pyrenoid. 
The nucleus is fusiform, and is surrounded by an envelope composed of 
intercrossing threads, and contains a nucleole. The protoplasm is 
therefore composed of distinct spirosparts. 
Prof. R. Chodat and M. O. Malinesco * * * § regard Scenedesmus and 
Dadylococcus as belonging to one and the same polymorphic genus, 
which may also occur in Pleurococcus, Gloeocystis , and Baphidium forms. 
From the absence of ciliated zoospores, the authors prefer to place 
Scenedesmus among the Pleurococcaceae rather than among the Hydro- 
dictyacese. 
Genera of Diatoms, f — M. J. Tempere gives a complete list of all 
generic names of diatoms employed since 1786, distinguishing those 
which he regards as well established. The name of one new genus, 
Leudugeria , is included. 
Atlas der Diatomaceen-Kunde. — Heft 46 of this magnificent work 
by Dr. A. Schmidt contains four beautiful folio plates (181-4). The 
species depicted belong mostly to the genus Melosira ; but there are 
some also belonging to Podosira, Butilaria, Actinodiscus , Adinoptychus , 
Craspedodiscus , Coscinodiscus, and Lepidodiscus. 
0. Schizomycetes. 
Bacteria in Vegetable Tissues.^ — Mr. H. L. Russell asserts that 
vegetable, like animal, tissues are normally free from micro-organisms, 
but that many species of bacteria may live in healthy tissues for a con- 
siderable time. A series of injection experiments showed that species 
which are pathogenic for the animal body — such as Bacillus anthracis , 
B. diphtherise , B. cholerse-g allinarum, Micrococcus tetragenus, M. cereus 
Jlavus, Staphylococcus epidermis albus, and S. pyogenes aureus — are killed 
in a few days by living vegetable tissues, with the exception of S. pyo- 
cyaneus, which may live for many days, and even increase. With regard 
to saprophytic species, — while some, like B. megaterium and B. lactis 
aerogenes, do not increase ; others were found after from 20 to 50 days in 
large numbers, and extending to some distance from the point of inocu- 
lation ; among these were B. prodigiosus, B. butyricus , B. luteus , B. coli 
communis , and B. Jluorescens. 
Diseases caused by Bacteria.§ — Herr W. Migula enumerates five 
diseases of plants caused by bacteria, viz. : — the pear-blight and apple- 
blight of the United States, caused by Micrococcus amylivorus ; the Sor- 
ghum-blight of America, due to Bacillus Sorghi ; the disease which attacks 
young maize-plants in America, due to an undetermined bacterium ; the 
disease of hyacinths ; and the damp rot of potatoes, caused by an aerobic 
bacterium, formerly confounded with Bacillus amylobacter. 
* Bull, de 1’Herbier Bossier, i. p. 184. See Morot’s Journ. de Bot., vii. (1893) 
Bull. Bibl., p. lvii. 
f Le Diatomiste, ii. (1893) pp. 17-20. t Bot. Gazette, xviii. (1893) pp. 93-6. 
§ Med. Proefstat. Midden-Java, 1892, 18 pp. See Morot’s Journ. de Bot., vii. 
(1893) Bull. Bibl., p. vi. 
