TRANSACTIONS OF THE SECTIONS. 45 
posed injurious excretions. To what extent this may be true, the microscope will 
best decide, by examining the roots and contiguous soil of plants after harvest, espe- 
cially those which have ripened seeds. 
2nd. Causes.—Fungi and mucors were supposed to bear somewhat the same re- 
lation to vegetable, as mites and the like to animal, life—a sort of debased or degraded 
vitality, produced when the organizing vital power was not enough predominant over 
the disorganizing tendency to decomposition, to effect due assimilation of the nutri- 
_ tious matter presented ; but still sufficiently so to prevent decomposition or decay. 
The constant struggle between the organizing vital force, and the decomposing power 
of chemistry, was described ; and instances were adduced to show that the invigora- 
tion of the vital force by solar light, and abundance of proper nourishment, enabled 
it effectually to repress the decomposing action; whilst, on the contrary, gloom, 
warm damp, and stagnant electrical air, assisted the disorganizing force, and often 
produced predatory fungi, which might thus be considered a sort of retarded disor- 
ganization. So ripening plants, as their vital powers decay, might generate such 
parasites, which would explain how they weaken the soil so much more than green 
crops, in proportion to the contents of their ashes. Such fungi, though not the 
cause of disease or decay, are effectual promoters of both, and probably the chief 
means of infection, where that also exists. 
3rd. Remedies.—If further investigation prove fungi thus generated to produce 
such generally injurious effects, the remedies will be of practical importance. These 
should be cheap and antiseptic, as well as destructive to fungi. Sulphate of copper 
with salt, which had been successfully used for seed potatoes, was too costly for 
spreading over the soil. Fresh lime, the general destroyer of noxious vermin, roots 
and seeds, would probably answer till rendered inert by carbonic acid. Salt, which 
appeared more promising, he had found, in some experiments, rather promote than 
destroy fungi. Lime and salt digested together would eliminate caustic soda, a very 
active destroyer; and soda ash, with or without lime, would have a somewhat like 
effect ; and ammoniacal gas liquor is perhaps a still more destructive application. 
But none of these alkalies can be regarded as antiseptic; and the ammonia, when 
neutralized in the soil, might even promote disorganizing fermentation where already 
too strong; and therefore, though they might do after seed crops, more antiseptic 
dressings must be used where there is putrescent tendency. Chloride of lime, in 
solution, he had found useless on diseased potatoes; the powder had been said to 
answer better, but either would soon be rendered inactive in the soil by the humous 
matters. Sulphuric acid, diluted, might succeed, where farmers had the means of 
applying it; and alum, which is of easy application, is a cheap and powerful anti- 
septic. 
Dressings of this kind, intended to kill the fungi and check the disorganizing 
action, would be turned under in the first ploughing after harvest, independent of the 
usual manure for nourishing and exciting vital action. 
New Facts bearing on the Chemical Theory of Volcanoes. 
By Prof. Dauseny, MD., F.RS. 
This communication detailed the views formerly promulgated by the author in 
support of that at one time entertained by Sir Humphry Davy, that volcanic phe- 
nomena are due to the oxidation of the metallic bases of the earths and alkalies by 
the access of water and atmospheric air to the interior of the earth. 
After alluding to the hypothesis of central heat, and pointing out in what respects 
it fails to account for the phenomena presented by volcanoes, Dr. Daubeny particu- 
‘larised two new facts which lend countenance to the chemical theory. The first of 
these is the chemical composition of volcanic products, which, according to recent 
researches, is such as to lead to the inference that they are derived from granitic 
materials, by the super-addition of those alkaline and earthy ingredients, which would 
arise from the supposed oxidation of the inflammable bases assumed to exist in the 
interior of the earth. 
The other new fact was the emission of flames from the orifices of Vesuvius and 
other volcanoes, attributable apparently to the combustion of hydrogen in some of its 
combinations, this disengagement of hydrogen being an immediate consequence of 
the supposed process, 
