SCIENTIFIC SUMMAKY. 
313 
of decomposing the cell walls, so as to gain admission to the tissues yery 
deeply. In some cases the effect of the presence of the parasite is to pro- 
duce a hypertrophy of the tissues, in hunt an intensity in the colour of the 
chlorophyll, or at least such an alteration of colour, that a practised eye will 
at once detect a hunted plant. In many cases, however, I douht whether 
the best microscopes will always detect fungus spawn, and such investi- 
gations require great caution, as the junctm’es of the cell walls are very 
deceptive.” 
Fungi in Flint. — At a meeting of the Chemical Society (April 2), Mr. 
W. Chandler Roberts read a paper, in which he described some singular or- 
ganic appearances which presented themselves in colloid silica, obtained by 
dialysis. He found this silica, on drying, to present a series of dendritic 
objects, which have all the characteristics of fungi. Mr. Roberts sup- 
posed them to be mimetic phenomena on the part of the silica. We 
have since, however, learned from Mr. H. J. Slack, who has been working 
at the subject, that these dendritic forms are nothing more than fungoid 
growths which have become imbedded in the silica, whilst in its liquid 
condition. Singularly enough the hardening and contraction of the silica 
does not appear to injure the soft structure of the fungoid arborescence. 
Is this because, previous to condensation, the silica had entered into the 
substance of the fungoid cells ? 
IVhy is Mould found in Carhonate of Soda ? — M. Le Rique de Monchy 
has published a note in the Comptes Rendus of the French Academy, in 
which he states that, in all the unfiltered commercial bicarbonate of soda 
which he has examined, he has found multitudes of what are styled 
molecular granulations.” These he believes to be nothing more than 
fungus spores, and he adds, they account for the production of vegetable 
matter in situations where one is surprised to meet with it.” 
The Morphology of the Pistil and Ovary. — The French Academy’s com- 
mission has reported on the three essays sent in for the Bordin prize for 
1867, and has awarded the prize to M. Van Tieghem for his labours. The 
author of the memoir considers that, before examining the distribution of 
the vascular bundles of the stem and ovary, it is necessary to understand 
exactly what is understood by the term axis, and what by the term appen- 
dicular. He then draws this distinction : when the vascular bundles are 
arranged in such a manner that in transverse section they form a complete 
circle, or, in other words, surround an ideal line, we have an illustration of 
an axis ; when, on the other hand, the vascular bundles are co-ordinated in 
relation to a plane, we have an instance of an appendicular organ. Starting 
with these definitions, the author proceeds to a minute anatomical analysis 
of over fifty-five families of plants, selected to illustrate all the com- 
binations of the organs whose morphology he desired to investigate. In 
order to avoid ambiguity, he has substituted for the term axile placentation 
the term angular placentation ; since the former is associated with a hypo- 
thesis, while the latter is not. Some of M. Van Tieghem’s conclusions will 
strike botanical readers as singular. For instance, he says that there are 
double appendicular organs which spring from the axis under the form of 
a simple bundle, and divide at a certain distance from the point of emer- 
gence into two simple superimposed appendices, and which may be said 
