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THE SCIENTIFIC HISTORY OF A PLANT 
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conveys it to the soil. Agriculturists find that the form in which it is given is of more importance 
than the actual quantity. Carbonate of ammonia is often found in large quantities ; but it is a volatile 
salt, and for this reason a very considerable quantity of the ammonia it contains is volatilized and lost. 
The object of gypsum as a manure is to produce that double decomposition by which is formed carbonate 
of lime and sulphate of ammonia, a more stable compound. 
The source of ammonia exhibits to us one of those beautiful and never-ending cycles of mutual 
sources of ammonia, relationship upon which the mind of the real observer of nature always delights to 
dwell. Throughout the physical world, from its first formation to the present time, there has never 
ceased to go on a perpetual mutation of matter — a ceaseless, ever-restless desire for change of form, 
and after some boundless wanderings, a turning back again, to undergo perchance the same work, 
though on a different subject — at a great distance from its former one — and after an inconceivably 
long interval had elapsed. 
" Communion with nature awakens thoughts that had long lain dormant," enthusiastically exclaims 
indestructibility of the author of the " Cosmos." Surely this sentiment must find within a hearty echo, 
matter - when for the first time we contemplate — actually by experimental demonstration — 
the imperishability and the indestructibility of matter : when, as in the case of the combustion of an 
organic substance with oxide of copper, the sugar, the volatile oil is destroyed, but its elements have 
assumed new forms, rendered cognizant to the senses by the balance. 
It is this great fact winch lends to my mind a charm — somewhat fanciful, I must admit — for the 
Transformations and science of geology. The thought that the oxygen — as carbonic acid was emit- 
changes of matter. ted so plentifully in the volcanic disturbances of the ancient world — which formed 
part of its atmosphere then passed into the composition of the flora of the gigantic vegetation of 
the coal-fields — the liberated oxygen in after ages uniting itself perhaps with a mineral, forming a 
sulphate — again to be reduced by organic matter to a sulphide — the carbonic acid freed again, passing 
off into oxygen by the vegetation of the oolite — taken up into the systems of the icthyosaurus — that 
this same oxygen, for what wc know to the contrary, may even now be helping to carry on in us the 
vital process — is still at work to change again — to become as pure and free as it ever was, and not 
different from ourselves, — never to wear out or to decay, but while the world lasts to be pursuing a 
destiny predetermined before its existence by the Great Author of nature. 
Ammonia is secreted from the body during life : it is a result of its putrefaction when dead. A 
Ammonia : its sources, thousand million of the human race, besides animals, annually die. How much 
nitrogen is thus given to plants is a question that I think it is beyond the limit of science to answer. 
But it comes round to us again, though not exactly in the same form ; for the plants supply the 
herbivora, who in their turn supply the carnivora. In some recent researches, I obtained from several 
Ammonia: a product coffins a nitrogenized compound called adipocere, rich in ammonia — in fact, an 
of putrefaction. ammoniacal soap. In all cases, on opening a coffin, there was a powerful odour of 
ammonia ; and as an illustration of the large amount of it in this adipocere, I may mention, that 
happening to have some in my pocket, on standing before a fire it began to melt ; some ladies at the 
same time observing, "What a very strong odour of hartshorn there is !" 
If all four can be represented by an oval, as some suppose — ah ova omnia — somewhat on the same 
Circular changes. principle, the actions of nature might be represented by a circle. The excrement of 
plants afford another example of circular change. Besides those which are gaseous and solid, there 
are some liquid excrements which are excreted by the roots and absorbed by the soil : these fluids arc 
very rich in carbon, so that the amount of that element which is furnished to the young plant by the 
humus is actually, by the secretions of the grown vegetable, returned again to it. 
But the greatest of all these circular changes is that which subsists between the animal and veget- 
Baiance between tbe a ^ e kingdoms — the principles of the two systems of hie requiring the refuse, the one 
of the other. It would be altogether out of place here to mention any statistics as to 
the large amount of carbonic acid derived from artificial combustion, from thermal 
springs, from extinct volcanoes, or from the respiration of animals ; but we know that if it were not 
removed the atmosphere could not for any length of time support life. But vegetation does this great 
work, and cultivation in most cases produces a purer atmosphere ; so these plants servo the animal 
kingdom in two ways— by supplying it with food, and by affording it a pure atmosphere. 
I can hardly conclude this sketch without making some reference to the origin of vegetable life, 
An hypouicsis pro- a subject which it is well to be cautious in approaching, because of the present 
imperfect state of our knowledge. Among the many theories of life (so, I suppose, 
they must be termed), although we cannot even attempt to reach ultimate causation, 
I may perhaps be allowed to express what may be termed a fancy of vegetable life (for theory is far 
animal and 
kingdoms. 
posed to account secon- 
darily for vegetable life. 
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