Botany. 333 
South American bark, in analysing which it is frequently difficult to 
purify the quinine from this adhesion. I obtained first from these leaves 
to the extent of 0°11 of alkaloid, of which part was soluble in ether, the 
remainder in spirits of wine, and afterwards 0°19 of precipitate still more 
combined with astringent matter. From these data, it seems to follow 
that the leaves will not supply a material for the extraction of quinine, 
put that they will, nevertheless, be very useful when used fresh or in 
recently prepared decoction or infusion for the cure of the fevers of the 
country. To this end the abundance of kinovic acid they contain, equal 
(weighed in the rough state) to 4°20 per cent., may also conduce. 
MISCELLANEOUS. 
Coagulation of the Blood.—Professor Lister, from recent experiments, 
concludes that the ammonia theory, however plausible, and though sup- 
ported by many ingenious arguments and experiments, must be discarded 
as entirely fallacious. The coagulation is in no degree connected with 
the evolution of ammonia, any more than with the influence of oxygen or 
of rest. The real cause of the coagulation of the blood when shed from 
the body, is the influence exerted upon it by ordinary matter, the contact 
of which, for a very brief period, effects a change in the blood, inducing 
a mutual reaction between its solid and fluid constituents, in which the 
corpuscles impart to the liquor sanguinis a disposition to coagulate. 
This reaction is probably simply chemical in its nature; yet its product, 
the fibrin, when mixed with blood-corpuscles in the form of an undisturbed 
coagulum, resembles healthy living tissues, in being incapable of that 
catalytic action upon the blood which is effected by all ordinary solids, 
and also by the tissues themselves when deprived of their vital properties. 
—Oreonian Lecture, Royal Society, 1863. 
Sir William Armstrong on the Consumption of Coal in Britain.— 
The statistics collected by Mr Hunt, of the Mining Record Office, show 
that at the end of 1861 the quantity of coal raised in the United King- 
dom had reached the enormous total of 86 millions of tons, and that the 
average annual increase of the eight preceding years amounted to 22 
millions of tons. By combining the known thickness of the various 
workable seams of coal, and computing the area of the surface under 
which they lie, it is easy to arrive at an estimate of the total quantity 
comprised in our coal-bearing strata.. Assuming 4000 feet as the greatest 
depth at which it will ever be possible to carry on mining operations, 
and rejecting all seams of less than 2 feet in thickness, the entire quantity 
of available coal existing in these islands has been calculated to amount 
to about 80,000 millions of tons, which, at the present rate of consump- 
tion, would be exhausted in 930 years, but, with a continued yearly in- 
crease of 23? millions of tons, would only last 212 years. It is clear that 
long before complete exhaustion takes place, England will have ceased to 
be a coal-producing country on an extensive scale. Other nations, and 
especially the United States of America, which possess coal-fields thirty- 
seven times more extensive than ours, will then be working more accessible 
beds at a smaller cost, and will be able to displace the English coal from 
every market. The question is, not how long our coal will endure before 
absolute exhaustion is effected, but how long will those particular coal- 
seams last which yield coal of a quality and at a price to enable this 
country to maintain her present supremacy in manufacturing industry. 
So far as this particular district (Newcastle) is concerned, it is admitted 
that 200 years will be sufficient to exhaust the principal seams even at the 
present rate of working. If the production should continue to increase 
NEW SERIES.—VOL. XVIII. NO. I11.—ocToOBER 1863. 2uU 
