94 
POPULAR SCIENCE REVIEW. 
BOTANY. 
The Mutability of Microscopic Germs . — On the 16th of November last M. 
J. Duval presented a note to the French Academy on the above subject, in 
which, referring to his former paper in the 11 Journal de l’Anatomie” for 
September 1874, he states that he has found a means of explaining both the 
doctrines of the panspermists and the heterogenists. And this explanation 
lies simply in the statement that he has discovered that the various so-called 
minute organisms (such as ferments) are simply one and the same organism, 
which has the power of becoming differently developed. He says thus : 
“ A trace of alcoholic yeast sown in media chemically appropriate has given 
birth to lactic, benzoic and ureic fermentations, and in every case I found the 
formation of a new special yeast for each fermentation. The transforma- 
tion of yeasts into one another is then possible, and it happens from all the 
evidence of these facts that the specificity of action of different ferments is 
a purely relative phenomenon dependent rather upon the composition or the 
state of the media than upon the proper constitution of these same organisms.” 
The paper from which this is taken is an extremely interesting summary of 
this author’s views, but it is in the essay in the 11 Journal de l’Anatomie” 
that the evidence in favour of it is to be found. 
The Carpellary Theory applied to the Liliacece and Melanthacece . — M. A. 
Trecul, one of the best physiological botanists in France, has been recently 
discussing the above theory, which he considers applicable to the two orders 
there given. He thinks they give new examples of the various modes of 
nervation which he has formerly described, especially in treating of Ranun- 
culaceas. He considers that they confirm the conclusion he has formerly 
arrived at. He enters on an interesting classification of the pistil and fruits 
of these plants, for which we must refer our readers to the memoir itself 
(“ Comptes Rendus,” t. lxxix., No. 20). 
Sphcer aphides in Plants. — On this subj ect a paper of some interest appears 
in the u Monthly Microscopical Journal ” for December 1874. The author 
states that in JJrtica dioica, U. urens, and Parietaria diffusa , the leaf-blades 
are studded with sphaeraphides, each about ^nd of an inch in diameter, 
globose, smoothish or granular on the surface, and all composed mainly of 
carbonate of lime. In the fibro-vascular bundles of the leaf are chains of 
much smaller sphaeraphides, each about j^th of an inch in diameter, rough 
from projecting crystalline points on the surface, and composed of oxalate 
of lime : and in the pith these small rough sphaeraphides are still more abun- 
dant. Both the leaf and pith of Humulus lupidus abound in like manner 
with the two kinds of sphaeraphides. In the leaf-blade these are crystalline 
concretions, made up of glassy granules, consisting of carbonate of lime. In 
the leaf-nerves, and in the pith of the stem, are thickly-set strings of rough 
sphaeraphides, in shape and chemical composition like those in the same 
parts of the nettles and pelletory. 
The Veins of Beech and Hornbeam Leaves. — Mr. Thomas Meehan, in a 
paper lately read before the Academy of Science of Philadelphia, said that 
De Candolle had noticed some j^ears since a difference in the venation be- 
tween the Fagus ferruginea and Fagus sylvatica, the common American and 
