238 Chronicles of Science. [April, 



concretions of a definite form, and of siliceous composition, which 

 are insoluble in acids, excepting hydrofluoric. M. Baillon describes 

 them minutely in Curatella Americana, a species which presents 

 these siliceous accumulations on both sides of its leaves. 



Gebmany. — On the Fecundation of the Fungi. — Professor H. 

 Karsten has published a very valuable memoir on this subject in the 

 * Botanische Untersuchungen,' 1866. He had observed the fruit of 

 a Lichen, the apothecium of Csenogonium, with all its spore- sacs and 

 paraphyses, forming an hymeneal stratum, develop itself from a 

 single cell, equivalent to a gonidial cell, and, indeed, after a previous 

 coalescence, and apparently after the mingling of its contents with 

 those of a branch of the cortical cells closely applied to its surface, 

 which is furnished with porously thin spots. — The question imme- 

 diately arose whether the fruit of the Discomycetes (which is in 

 part constructed in the same way) as well as those of other allied 

 tubular Fungi, and even those of the Hymenomycetes, were not 

 produced in consequence of a similar process of copulation. The 

 investigation of the development of the leafy cellular Cryptogams 

 supports the supposition that this mode of development occurs also 

 in the other composite fruits of the Lichens and Fungi. Professor 

 Karsten in pursuing this question has dissected and observed the 

 developmental history of the fruits of numerous Fungi (Agaricus, 

 Peziza, Helvetia), and records his observations in this paper. The 

 following simple laws as to the multiplication of plants, results from 

 the confirmation of his views : — 



1st. The typical form of every true species of plant is propa- 

 gated and maintained by sexually produced germs. 



2nd. Whilst the fecundated germ-cell is developed in the Pha- 

 nerogamia into a single germ, which usually rests in its envelopes 

 for a longer or shorter period, and in the vascular Cryptogamia into 

 one which evolves itself at once, in the cellular Cryptogamia it is de- 

 veloped generally into a composite fruit containing numerous seeds. 



On Rotation and Circulation in the Cells of Plants ivith re- 

 ference to the question of Contractility. — Professor Keichert has 

 recently published the results of his investigations on this most 

 interesting series of phenomena. Considered together with the in- 

 valuable observations of Professor Max Schultze on the movements 

 of the Diatomaceae and vegetable protoplasm, they afford a compre- 

 hensive view of the subject. Professor Eeichert maintains that — 



1st. In all vegetable cells with rotating, circulating, or rotato- 

 circulating currents, two parts are to be distinguished in the con- 

 tents of the cellulose capsule, namely, the central " cell-juice " or 

 " cell-fluid," situated in the axis, and the mantle-layer, diffused 

 between this and the cellulose capsule. 



2nd. The " cell-fluid " is motionless, colourless, and non-tena- 

 cious ; the " mantle-layer " consists of — first, a fluid basis, the 



