THE WONDERS OF THE VEGETABLE KINGDOM. 
NO. VI. 
What is a Tree? 
<• x care not liow men trace their ancestry, 
To Ape or Adam; let them please their whim; 
But I in Juno am midway to believe 
A tree among my far progenitors; 
Sucli sympathy is mine with all tiie race, 
Such mutual recognition vaguely sweet 
There is between us. Surely there are times 
When they consent to own me of their kin, 
And condescend to me, and call me cousin, 
Murmuring faint lullabies of eldest time 
Forgotten, and yet, dumbly felt, with thrills 
Moving the lips, though fruitless of the words.” 
— Lotvcll. 
There is no ono object in Nature that has been the 
cause of so much discussion, about which there has been 
so much written, or one that so justly claims our atten¬ 
tion, as the tree. What is a tree? What are its func¬ 
tions, and how are they performed ? For what was it 
created? What is tree life, and how is it sustained? 
Upon what does the tree feed, and how is growth de¬ 
veloped ? From whence come those annual circles of 
woody fibre, and those annual productions of leaf and 
root in spring, and the regular decay and fall of both 
in autumn? From whence comes the delicious fruit, 
and what is the fragrance of the flower? All interesting 
questions, beautiful thought, shrouded in those delicate 
yet gorgeous robes of mystery with which nature 
clothes all her works. 
St. Augustine, said: “ When no one asks me what is 
time, I know it very well; but I do not know it when 
I am asked.” Cannot the same be said of the tree, 
which is one of the most familiar objects in Nature? We 
see and admire, but wo cannot define. 
From a long series of interesting experiments and ob¬ 
servations made by those distinguished scientists, 
Mirbel, Mold, Schleiden, and a host of others, with the 
aid of the microscope and the most complete chemical 
apparatus that human ingenuity can devise, we find there 
is a constant interchange of gases between the plant 
and the atmosphere, exhibiting the double phenomena 
of absorbtion and exhalation, winch is analagous to the 
respiration of animals. 
Loaves, by a natural process of their own, absorb car¬ 
bonic acid gas, winch is denominated fixed air, and give 
out oxygen gas or pure respirable air; for if placed in 
air that has been rendered so impure as to be unable to 
support the flame of a candle or animal life, they will 
thrive, and soon restore it to its purity. Hence it is 
obvious that the oxygen of the whole atmosphere 
would, in the course of time, be consumed by the 
breathing of animals and by flame, were it not for this 
singular provision, which enables the leaves of plants to 
supply oxygen, and to keep up the due proportion 
which is necessary for the support of animal life. 
Mirbel observes, in reference to this extraordinary 
fact, “that plants alone have a power of deiiving nour¬ 
ishment, though not exclusively, frcm inorganic sub¬ 
stances, mere earth, salts or air: substances certainly 
incapable of serving as food for animals, since these 
feed only on what is or has been organized matter, either 
of a vegetable or mineral nature, so that it would seem 
to be the office of vegetable life to transform dead 
matter into organized, living bodies. Many aquatic 
plants possess the faculty of throwing out pure air in a 
remarkable degree, particularly the Epilobium or 
Willoio-lierb and the Conferva, a minute, branching, 
cotton-like vegetable, which grows on putrid water, 
especially that which has been rendered foul by long- 
keeping on ship-board, which it purifies and renders fit 
for use.” 
The gases which the plant absorbs from the atmos¬ 
phere are usually considered plant food, and to a large 
extent contribute to its growth. To a certain extent 
this is true, although plant growth or development, is a 
result, an effect. The operations which produce the same 
we will endeavor to show. 
The changes that plant food undergoes are purely 
chemical, and are in all respects similar to the changes 
in animal food. The food of plants is digested and ren¬ 
dered nutritive in then- leaves, that of animals in their 
stomachs; in both the operations are the same, and are 
performed in the same manner as the chemist separates 
elementary substances. 
When starch is converted into glucose, or grape- 
sugar, as it is commercially known, it is done by the 
addition of a small quantity of sulphuric acid, when it 
is in a liquid state, and then by submitting to a great 
heat. To free the acid, a small quantity of the car¬ 
bonate of lime is thrown in: this precipitates the acid, 
and the then combined foreign elements settle to the bot¬ 
tom of the tanks, leaving the glucose pure, which, at con¬ 
venience, is drawn off, and the combined chemical 
agents, being of no further use, are committed to the- 
rubbish heap. In separating iron from the ore, car¬ 
bonate of lime is an important chemical agent. The 
ore and the limestone, in proper proportions, are put 
into the furnace and submitted to a great heat, which 
sets the iron free, all foreign matter unites with the 
lime, forming a mass known as flux, which is simply in 
the mechanic arts waste matter. 
In these operations art only imitates Nature; in the 
transformation of impure gases into pure oxygen by the 
plant, the same operations take place, the same elements, 
are employed, and there is the same waste matter to be 
disposed of. In order to show how this important work 
is performed, we must commence with the seed, and 
repeat some familiar lessons. When we plant a seed in 
the ground, it very quickly commences growth in two 
opposite directions, upwards into the atmosphere, and 
downwards into the earth, the two sources from whence 
it obtains the materials which contribute to its future- 
growth. The first change the seed undergoes is the 
conversion of the starch which it has stored up into 
sugar, the food of the infant plant; this is done on pre¬ 
cisely the same principle that starch is converted into 
sugar at the starch manufactory, the only difference- 
