October, 1881. 
THE CHEMIST AND DRUGGIST. 
47 
the temperature of 1 lb. of water was raised 1° F. by the 
expenditure of an amount of force sufficient to raise 772 lbs. 
to the height of one foot. The conclusion arrived at was that 
the quantity of heat capable of raising the temperature of 
1 lb. of water (between 55° and 60°) by 1° F. requires for its 
evolution the expenditure of a mechanical force sufficient to 
raise 772 lbs. one foot (Phil. Trans., 1859). (Chemical 
affinity, heat, light, magnetism, and electricity were here 
briefly touched upon.) 
Matter (the various substances of which the universe is com- 
posed) is resolvable into simple elementary bodies. Iron, 
gold, silver, oxygen, &c., are simple bodies; and so on to some 
61 undecomposed substances. Water (II 2 0) is a compound 
body. Of these elementary substances only 14 occur in large 
quantities: — C, H, O, N, P, S, Fe, Ca, Mg, K, Na., Al., Cl., Si. 
(The lecturer here made remarks on the soil and atmosphere 
and the above constituents of plants and animals.) Organised 
beings have been arranged under two heads, two great divisions 
— animals and plants ; and, although the lowest genera in each 
division approximate so closely that it is almost if not quite 
impossible to fix where one begins and the other ends, yet in 
their general relationships they are widely different, and 
opposed to each other in the functions which they discharge 
in the order of nature. The operations of vegetable life are 
complementary to those of animal life in the nicely adjusted 
balance of organic life, each affording support and nourishment 
to the other, and mutually dependent. (The contrast between 
animals and plants was explained by diagrams.) 
There are observers of repute who maintain that there are 
certain organisms which are animals at one period of their 
lives and plants at another, and vice versa. The recent investi- 
gation of De Bary have an important bearing upon this question. 
He describes certain fungi, the spores of which, when germinat- 
ing, give rise to a body undistinguishable from the ameba, one 
of the lowest forms of animal life. However, we know that 
plants have a place in nature intermediate between minerals 
and animals, and derive their nourishment from the earth 
and atmosphere, and that plants alone have the power of 
converting the inorganic, or mineral, matter into organic. 
Animals live on organic matter, and reconvert it into in- 
organic. Animals cannot produce protoplasm. Professor 
Huxley, in his work on the Physical Basis of Life , says 
“ that a unity of power or faculty, a unity of form, and 
a unity of substantial composition pervade the whole living 
world.” The attempt to define or explain the phenomena of 
life in plants or animals has been made, but we are not called 
upon to detail the various metaphysical and scientific definitions 
here. Of one thing we are certain — that all the pheno- 
mena of life in plants are due to solar radiance. The 
undulations of the sun’s heat penetrate the soil, and set 
in motion the atoms of the rootlet, and enable them to 
shake hydrogen atoms out of equilibrium with oxygen 
atoms, which cluster about them in the compound molecules 
of water. The swifter undulations are arrested by the leaves, 
and enable them to dislodge atoms of carbon from the carbonic 
acid in which they move. These disturbances of equilibrium 
cause a series of rhythmical motions in the form of the alter- 
nately ascending and descending sap. Cells and fibres are then 
developed. Plants are “ the air-woven children of light.” As 
only in special physical conditions can vegetable life exist, so 
it is also with the animal. In that collection and combination 
of substance which constitutes an animal there is a per- 
petual introduction of fresh matter, and a constant departure 
of the old material. The permanence of the individual 
depends upon the permanence of external conditions. As 
they change, so it changes, and a new form is the result. 
That which we call life is the display of the manner in which 
the force thus disengaged is expended. As has been said by 
Draper, a scientific examination of animal life must include 
two primary facts — it must consider in what manner the stream 
of material substance has been derived ; in what manner and 
whither it passes away; and since force cannot be created from 
nothing, and is in its very nature indestructible, it must deter- 
mine from what source that which is displayed by animals has 
been obtained, in what manner it has been employed, and what 
disposal is made of it eventually. As pointed out before, the 
force expended is originally derived from the sun. 
Plants are the intermediate agents for its conveyance. The 
inorganic saline material of which they are composed is derived 
from the soil in which they grow, and also the greater part of 
the water so essential to their existence. The organic matter 
of plants is derived from the air ; and so we may say, to use 
the words of Mottschut again, “ they are the air- woven children 
of light,” condensed from the air. 
The chemical explanations of vegetable physiology rest 
principally upon the discovery of oxygen by the illustrious 
Priestley, carbonic acid by Lavoiser, and the composition of 
water by Cavendish and Watt. 
When the sun shines the leaves of plants decompose carbonic 
acid, one of the ingredients of atmospheric air ; this substance 
is composed of the two elements, carbon and oxygen. The 
carbon is appropriated by the plant, and enters into the com- 
position of the sap, from which organic products, such as starch, 
sugar, wood-fibre, &c., are made. The oxygen now liberated 
from the carbon is for the most part refused by the plant, and is 
returned to the air , and as the process goes on, fresh portions 
of carbonic acid CO 2 are ready to be absorbed and decom- 
posed. The leaves are trembling in an atmosphere warmed by 
the sun’s rays, and over their surface warm currents are con- 
tinually passing. 
The plant’s function, then, is to separate the combustible 
carbon from the air. Carbon is thus obtained from carbonic 
acid C0 2 and H from water H 2 0. Plant life is, chemically 
speaking, an operation of reduction. Plants decompose in a 
similar way ammonia into its constituents, nitrogen and 
hydrogen ; and sulphuric acid and phosphoric acid are made 
to give up their oxygen, the phosphorus and sulphur being 
appropriated. The whole vegetable world has thus been and 
is the result of the solar radiance, formed of matter once 
united to oxygen. In the wonderful series of decompositions 
which take place in the plant, force or energy, in the form of 
light, has disappeared and become incorporated with the 
organic matter of the vegetal organism. This force is ready 
to be given up again when oxidation takes place — e.g ., coal in 
our fires. Vegetable products constitute a magazine of force 
ready for our use ; hence their adaptation to our wants as 
food, and for the production of warmth. The plant in the 
secondary geological periods locked up the carbon in its 
tissues for future ages ! ! Oil, fat, wax, &c., like coal, 
have all derived their carbon, or force-giving properties, 
from the sun. “When one takes,” says Professor Fiske, 
“a country ramble on a pleasant summer’s day, one may 
fitly ponder upon the wondrous significance of this law 
of the transformation of energy. It is wondrous to reflect 
that all the energy stored up in the timber of the fences 
and farmhouses which we pass, as well as the grindstone and 
the axe lying beside it, and in the iron axles and heavy tires 
of the cart which stands tipped by the roadside ; all the 
energy from moment to moment given out by the roaring 
cascade and the busy wheel that rumbles at its foot ; by the 
undulating stalks of corn in the field, and the swaying 
branches of the forest beyond ; by the birds that sing in the 
tree tops, and the butterflies to which anon they give chase ; 
by the cow standing in the brook, and the water which bathes 
her lazy f:et ; by the sportsman who passes, shooting in the 
distance, as well as by the dogs and guns ; — that all this multi- 
form energy is nothing but metamorphosed solar radiance, and 
that all these various objects, giving life and cheerfulness to 
the landscape, have been built up into their cognisable forms 
by the agency of sunbeams, such as those by which the scene 
is now rendered visible. We may well declare with Professor 
Tyndall that the grandest conceptions of Dantd and Milton 
are dwarfed in comparison with the truths which science 
discloses. But it seems to me that we can go further than 
this, and say that we have here reached something deeper than 
poetry. In the sense of illimitable vastness with which we 
are oppressed and saddened as we strive to follow out in 
thought the eternal metamorphosis we may recognise the 
modern phase of the feeling which led the ancient to fall 
upon his knees and adore — after his own crude symbolic 
fashion — the invisible Power, whereof the infinite web of 
phenomena is but the visible garment.” 
The lecturer alluded to the sanitary influences produced by 
plants, the purification of the air, the disintegration of the 
soil by the roots of trees, the drainage of the soil, the import- 
ance of the conservation of forests, the disastrous results which 
had ensued in many parts of the world through the wanton 
and ignorant destruction of forests ; and, in conclusion, made 
the following remarks upon the exhalation of water by leaves 
and the preservation of forests : — 
A common sun-flower, 3^ feet high, with a surface of 5’ 616 
square inches, exhaled 20 ounces a day (Hales). If 
such a large amount of fluid be thus given off by a single 
plant, what an enormous quantity must be exhaled by 
