104 
POPULAR SCIENCE REVIEW. 
structures in the capillaries of man. If the thistle he watched at the 
period of flowering, it will be seen that the anther-tube is slightly elevated 
above the corolla, and that on being touched pollen masses make their 
escape, whilst the tube exhibits a curious twisting movement. However, 
this discovery is not more remarkable than that of the movements of the 
stamen-filaments in the Berberidacece and other orders of plants. 
The Evolution of Buds . — A number of memoirs on this subject have 
been presented to the French Academy by M. Ch. Fermond; but the 
descriptions and generalizations are expressed in technical terms of so 
entirely novel a character that we must refer the reader to the originals for 
an idea of what the author intended to convey . — Comptes Rendus , July 
20 and August 24. 
The Artificial Development of Ascophora nigrans .■ — This plant, which is 
easily developed naturally in organic matter, has been produced by M. 
Raulin in artificial solutions. He finds also, that it affects certain salts 
rather than others, and gives the following as the results of his investi- 
gations: — The most suit able mineral substances are in order of importance — 
phosphorus, potassium, magnesium, sulphur, and manganese. A liquid 
holding all these substances in solution will, in a certain fixed time, 
develop 20 grammes of this plant ; another, which differs from the first by 
the absence of manganese, produces only 5 grammes in the same period of 
time ; the suppression of sulphur reduces the supply to 2 grammes, that 
of magnesium and potassium to 1 gramme, and that of phosphorus to 
0*5 grammes. The quantities of these elements which must be employed 
form a very fractional part of the weight of the plant which is produced, 
less than two-hundredths in some cases. From several experiments which 
he has made, M. Raulin is enabled to conclude that free nitrogen is not 
absorbed by these plants. 
Coloration of Vegetable Tissues by Acids . — The coloration which acids 
impart to the tissues of plants has received the attention of botanical 
chemists for some time past. Not the least distinguished of those who 
have given the subject consideration is M. A. Guillard, who now makes 
known the opinion he has formed. Acids, according to this investigator, 
exert an action not only upon portions of the liber , but they tinge com- 
pletely the woody tubules and vessels, the medullary rays and even the 
central pith itself. Violet, with its various shades, is not the only colour 
exhibited on addition of a drop of hydrochloric acid ; in some plants, as 
Staphykea and Dianthus, a beautiful green is developed : in the liber of 
Sagina and Plumbago, and in the leaves and fibres of Myrica, a yellow is 
observed, whilst the Epacridese yield a splendid orange hue. This pro- 
duction of hues has been observed more frequently among dicotyledons 
than other groups, and the author considers it to be a fact of much 
importance in connection with the examination of the microscopic struc- 
ture of vegetable tissues. 
On the Germination of the Organic Corpuscles which are found in the 
Atmosphere. — M. Duclaux is engaged in a series of experiments on the 
germination of mould spores, and publishes the results he has already 
arrived at. He collects the spores on cotton by Pasteur’s apparatus, and 
then steeps the cotton in a liquid containing sugar, some mineral matters, 
