SCIENTIFIC SUMMARY. 
303 
contributor to these pages) delivered before the Royal Institution (April 16) 
the lecturer explained wby we have no true cellular plants in the coal. The 
long-continued maceration; said Mr. Carruthers, to which the coal plants were 
subjected when the beds composed of the remains were forming on the 
surface of the earth; and the subsequent changes they have undergone; have 
reduced to one common structureless mass the varied vegetation of which 
the coal is composed. One of the first results of these operations would be 
the disappearance of the cellular plants which under the then existing very 
favourable conditions must have abounded; just as the soft cellular parts 
are almost always destroyed of those specimens which have been so favour- 
ably situated as to have their vascular tissues preserved. 
The Physiological Phenomena of Plants explained Physically. — Those who 
have paid any attention to the recent progress of physical research are 
aware thatM. Becquerel has lately described some very remarkable pheno- 
mena; under the title of Electro-capillarity. Quite recently he has been 
applying these observations to physiology, and in the Comptes-Pendus for 
June 7 he attempts, by means of electro-physics, to explain some of the 
functions of plants. His experiments on the tissues of plants, which he 
regards as made up of a number of electro-capillary couples, lead, he says, 
to the following results : — 1. The stem of a dicotyledonous woody plant 
consists of two distinct parts, separated by a substance which is the 
principal element in growth, the outer part is the bark, the inner the wood. 
2. The wood is formed of medullary rays, woody bundles, and of a cellular 
tissue called the pith, and of concentric layers ; the bark likewise includes 
a fibrous and cellular element, only these parts are inverted ; the parenchyma, 
which is analogous to the pith, occupies the outer part of the bark, while 
the pith is in the centre of the woody tissue. This inversion has 
electrical analogues. 3. In the wood one finds an electrical condition 
contrary to that of the la 5 ^er which follows or which precedes it. 4. The 
central part, or pith, is always positively electrified, in relation to the 
woody layers, and these are less and less positive as one approaches the bark. 
In the latter the conditions are reversed. M. Becquerel then describes a 
number of very interesting experiments tending to support his idea that the 
motion of the fluids of plants is due to phenomena of electro-capillarity. 
CHEMISTRY. 
Positivism and Idealism in Chemistry. — The following remarks, which we 
commend to the serious consideration of some chemists of a too speculative 
turn, were made by Dr. Odling in his recent lecture before the Royal Insti- 
tution : — “ The existence of a determinate structural arrangement in chemical 
compounds is demonstrated by a host of considerations ; but the difficulty 
of making out the actual structure of individual compounds has hitherto 
proved insuperable. The facility of setting forth imaginary structure, how- 
ever, is very great; and accordingl}’- the presentation of imaginary for 
ascertained structure has been freely practised by chemists from the fii-st 
introduction of chemical formulae until now. But in what degree soever a 
VOL. Till. — NO. XXXII. X 
