81 
OF GARDENING AS A SCIENCE. 
NO. IV. 
In following up the subject which we commenced in the last number, p. 55’ it 
will be requisite to enter somewhat at large upon the investigation of that substance 
which, under the name of humus , has recently engrossed much of the attention of 
agricultural writers : gardeners, however, have said little about it, though, if it be 
the nutritive principle of vegetation, they are as much concerned in it, if not more 
so, than is the farmer. About ten years since, the reading public became interested 
by the importance which was attached to a certain matter in the soil, which had 
suddenly assumed the title of humine : this word went its round, till at length dis- 
covery was made that pearl-ash and soda, as well as lime, exerted a peculiar action 
upon it ; and then the term humic acid came into vogue. Now, however, the 
same substance has acquired the more simple term of humus , a Latin word, which 
means the soil or ground, or, in its new acceptation, the fertilizing principle of the 
soil. We will not quarrel with terms, for 44 what is in a name ?” but content our- 
selves by showing, from Dr. Liebig’s plain recital of facts, that authors and readers 
are pretty nearly in the same predicament, and understand little of the philosophy 
of their fashionable subject. — Thus, at p. 4 et seq. of 44 Organic Chemistry,” we 
find that — 
44 Humus is described by chemists as a brown substance, easily soluble in 
alkalies, but only slightly soluble in water, and procured by the decomposition of 
vegetable matters by the action of acids or alkalies. It has, however, received 
various names, according to the different external characters and chemical properties 
which it presents. Thus ulmin , humic acid , coal of humus , and humin , are names 
applied to modifications of humus. They are obtained by treating peat, woody 
fibre, soot, or brown coal with alkalies ; by decomposing sugar, starch, or sugar-of- 
milk by means of acids ; or by exposing alkaline solutions of tannic and gallic acids 
to the action of air.” 
The reader should bear in mind that the substances thus alluded to, are pure 
results of experiments in the laboratory : by a grasping after novelty, an assumption 
of the air of science, or by a sort of mental obliquity, modern agricultural teachers 
have assumed that their humine or humus is identical with the humus of the 
chemist ; whereas, — ■“ Not the slightest ground exists for the belief that one or 
other of these artificial products of the decomposition of vegetable matter exists in 
nature in the form, and endowed with the properties, of the vegetable constituents 
of mould ; there is not the shadow of a proof that one of them exerts any influence 
on the growth of plants, either in the way of nourishment or otherwise.” 
In other words, writers have identified the matter of 44 earth laborated manure ” 
with the artificial humus of chemistry ; and observing a scantiness of growth where 
VOL. VIII. NO. LXXXVIII. 
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