Chap. XII. ArrENnix, Part 4. No. 1.

105

bles be submitted to combustion in the open air, and it will beteen how smail a portion remains, after all the volatilizable partsare vanished. Now, a rapid fermentation is only a silent com-bustion, the final result being the same. But besides the lossof hydrogen itself thus dissipated, its use as a solvent is alsolost. The hydrogen of vegetable, and the azot of animal sub»stances are the best, and perhaps the only solvents of carbon ;and the liquid compound formed by them, as it issues from pu-trefying substances, is the very essence of vegetable aliment. *It would seem therefore highly economical to restrain the fer-mentation within moderate bounds, and mix the manure iviththe soil before it has proceeded too far.

But there is a notion handed down by tradition, that rank orfresh dung is injurious to vegetation; and those who hold thatnotion, support it by a position advanced by a learned Lord,whose valuable communications have been already alluded to.Lord Meadowbank, in the introduction to his inestimable essayon the preparation of peat moss for manure, says, the early char-ges f in the putrefactive fermentation) appear rather to he perniciousto vegetation, 'when plants are exposed to their direct effect; the laterchanges powerfully promote the growth of plants. His Lordship iscertainly quite correct in this as a general position. In all sub-jects which contain so much saccharine matter as to he capableof regularly undergoing the vinous, acetous, and putrid fermen-tations, both the spirit and the acid are pernicious. Dr Halesmade a plant imbibe spirits which occasioned the immediate ces-sation of vegetable life: j- and by some late experiments it ap-pears that acids are equally deleterious. J Such a subject there-fore promotes vegetation only in the later changes, when bothspirits and acids are decomposed. But the composite substancein question, containing little or no sugar, is not of this descrip-tion : the ingredients, however, being of different qualities, mustbe examined separately. None of our dead vegetables, except

* Sennebicv expresses a doubt of plants being nourished by this solution,with which it is presumed no practical agriculturist will concur. He placedsprigs of the raspberry plant, without roots, in vials filled with dung juice, witha mixture of the same liquid and water, and with pure water. The sprig inthe unmixed juice imbibed only 20 grains, and withered in 4 hours ; the sprigin the mixture imbibed 40 grains, and withered in the coui’se of a day; thesprig in pure water had imbibed 800 grains in that time, and was still lie^h.■fhis experiment was in part repeated. On two small vials, one filled with halldung juice, half water, the other with pure water, two sprigs of mint, withroots attached to them, were placed. The plant on the first did indeed for sometime imbibe less than the other. Fresh water was daily added, to supply whathad been imbibed, till the mixture became limpid, and the plant on the one vial,imbibed as much as that on the other. During this time the plant on the purewater had made little advance, but that on the mixture had a deeper green, and^ a d put forth many leaves.

f Vegetable Statics.

i-Xaisinith’s Elemcnfs ®f Agriculture, p. 67, 6S, and 74.