ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
73 
From another series of experiments made with S. apiculatus by 
inoculating it in a medium containing ammonia salts, dextrose, and 
invert sugar, it was ascertained that a percentage volume of 4 - 12 was 
reached in about one year. The distilled alcohol contained fusel oil. 
The volatile acids consisted of formic acid, acetic acid, and of a small 
quantity of an acid boiling at 120°-125°. The non-volatile acid con- 
tained succinic and lactic acids. The fact that S. apiculatus produced 
in sixteen days O' 79 per cent, by volume of alcohol from beer-wort, and 
that it took almost one and a half years to produce less than double this 
quantity, showed that, besides the quickly fermenting dextrose, there 
must be present other sugars which ferment quite slowly. 
Nitrification.*— From a series of experiments carried on in the 
laboratory with porous bodies, M. H. Bordier has come to the conclusion 
that the production of nitric acid which takes place in the soil, may, at 
least to a large extent, be attributed to the oxidizing influence of tho 
air which percolates the interstices of the soil, the circulation of this 
air being promoted by constant changes of temperature (thermo- 
diffusion). 
y. General. 
Action of the Colours of Flowers on Photographic Plates.f — 
Noticing that the flowers of Sicyos angulata were very largely visited 
by insects, notwithstanding their small size and light green colour, 
Dr. P. Knuth has made a series of experiments with a view of deter- 
mining the relative intensity of the action of flowers of different colours 
on photographic plates. He found the order of succession to correspond 
with tho curve of the chemical rays of the spectrum, except that tho 
light-green flowers of Sicyos and Bryonia came out earlier and stronger 
than would have been expected. Further experiments convinced the 
author that the phenomenon is due to the flowers of these plants giving 
out ultra-violet rays ; and the inference follows that, as insects can detect 
tones higher than those audible to the human ear, so they can detect 
rays of light invisible to the human eye. Direct observations showed 
that the flowers of Sicyos angulata possess about half the intensity of 
pure white flowers. 
Fossil Dicotyledones.f — M. G. de Saporta records the discovery of 
some very interesting fossil remains of plants at Cereal in Portugal in 
strata lying between the Cenomanian and the Neo-jurassic, and incum- 
bent on the latter. They include about thirty-five species, of which 
about one-half are Cryptogams. Among these the most abundant are 
several species of Sphenopteris, and there is also a remarkable new species 
allied to Isoetes, Isoetopsis Choffati. Among Gymnosperms there are 
five Conifers. Among Monocotyledones were found species of Poacites, 
with grass-like leaves resembling those of Zostera, and Protolemna, 
apparently allied to our existing Leninas. But the most interesting 
remains found were those of a plant which the author calls Protorhipis 
Choffati, with reticulate-veined leaves, and which he regards as repre- 
senting an archaic and very lowly organized type of Dicotyledones, but 
* Mem. Sci. Phys. et Nat. Bordeaux, v. (1890) pp. 185-238. 
t Bot. Centralbl., xlviii. (1891) pp. 161-5, 314-8 (12 figs.), 
t Comptes Reudus, cxiii. (1891) pp. 249-53. 
