The Plant And Its Food 
By Burt L. Hartwell, Rhode Island 
IT is true that life is a mystery and that it will remain 
a mystery in spite of the efforts of a multitude of 
investigators and observers for at least a long time 
to come. The life of a plant is shrouded with a full share 
of the so-called mystery which is assigned to life in gen- 
eral ; if by mystery we refer to what is unknown. How- 
ever, by asking ourselves questions concerning the 
growth of plants and searching the literature diligently 
for the answers, a fairly clear conception may be ob- 
tained in time of what is transpiring in the vegetable 
kingdom about us. We shall, of course, fail as yet to 
find answers to a great many of our questions, and the 
reply to others will be like that often attributed to the 
Yankee — merely another question. Yet the search is 
worth the candle, for aside from economic considera- 
tions, an intense interest and pleasure rewards the 
searcher in the world of plants. 
It is hoped that a few glimpses may be given which 
shall be sufficiently plain to cause some of the mysteries 
to disappear ; others will be left untouched and un- 
noticed as furnishing more suitable subjects for the dis- 
agreement of doctors and for the theories of specialists. 
Words which have been coined to designate a particular 
part of a plant or some phenomenon concerning its 
growth, and which are more or less unfamiliar, will be 
avoided as much as possible for it is desired to relieve 
you of a burden of difficult names so that the mind may 
be left free to consider the plant as a whole. 
The culmination of the growth of the plant is the pro- 
duction of the seed and as from the seed again proceeds 
the new plant, our attention may well be directed to this 
starting point. Warmth and moisture acting upon the 
food stored in the seed bring about chemical and physical 
changes which result in the tiny sprout and the rudi- 
mentary root. The supply of food from the seed being 
soon exhausted the little plant is obliged to change its 
mode of life in order to secure nourishment from the air 
and soil. To understand how it is possible for the voting 
plant to shift for itself, a glance through the microscope 
must be taken at the make-up of our little individual. 
Thin slices or sections stained successively with different 
dyes, reveal the fact that various layers and parts behave 
very differently as regards their ability to absorb the sev- 
eral dyes, one portion taking one color and another por- 
tion a different color, and it becomes possible, thereby, to 
differentiate, and to call by name, these various colored 
parts. As it is always easier to remember faces than 
names, let us confine our attention to the picture and not 
trouble ourselves much with the names. 
The entire plant will be found to be composed of tiny 
cells, some comparatively long and narrow, others short 
and wide. Without the help of the microscope one would 
hardly suspect this and would certainly have no concep- 
tion of the different parts constituting the living cell itself. 
The entire envelope or covering of each cell, called the 
cell-wall, is a somewhat rigid, porous layer which 
changes in composition as the plant grows older, grad- 
ually becoming tougher, until the contents of the cell die 
and become absorbed. Wood is composed of these dead, 
toughened cell-walls. In every living cell, within and 
pressed against the cell-wall, is a substance which is 
called protoplasm, having many properties in common 
with the white of an egg. In some cases this substance 
nearly fills the cell and again large spaces are left in the 
central portion with bands only of the protoplasm stream- 
ing through them. The protoplasm is not a homogeneous 
substance, but contains portions of greater density and 
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more or less definite form, notably the nucleus, to which 
are attributed somewhat poorly understood functions. 
Even in those cases where the protoplasm comprises but 
a small part of the cell-contents, it conforms closely to the 
inside of the cell-wall and acts as a door-keeper, deter- 
mining what shall pass into the interior of the cell, or Out 
through the wall. The spaces within the cell, which arc 
left unoccupied by the protoplasm, are rilled with the sap 
of the plant. This sap is composed of water carrying 11* 
solution the food which serves partly for the formation 
and nourishment of the protoplasm which in turn builds 
up the cell-wall. Picture to yourself thousands of such 
cells modified into a great variety of forms and descrip- 
tions, some so long and so devoid of protoplasm as to be 
little more than tubes for the rapid transit of water and 
food-stuff, others again which are dead and comprise 
only the woody walls for supporting and bracing pur- 
poses, and you will have before you a plant, and will be 
in a position to trace some of the operations going on in 
the same. 
Considering the amount of attention which is given to 
fertilizing crops, it might seem as though nearly all of 
the plant's supplies are obtained from the soil-, but we 
know that carbon which makes up so large a part of the 
plant comes from the carbonic acid gas in the air. This 
is the gas which is exhaled from the lungs of animals, 
and the plants perform a great service for us by prevent- 
ing an undue accumulation of this gas which would in- 
terfere with respiration. The plant also uses oxygen 
from the air. 
The organic substance of the plant is formed by the 
agency of sunlight acting in connection with the green 
coloring matter, especially in the leaves. Carbonic acid gas 
and oxygen are not the only raw materials necessary to 
the formation of organic matter. There must be present 
also, water and certain saline substances or salts. The 
water and salts are obtained from the soil and are trans- 
ported to the leaves through the long tubular cells which 
have already been mentioned. Water is not only needed 
in the elaboration of the organic matter, but also to re- 
place that lost by evaporation from the leaves, etc. There 
is, then, during active growth, a continual movement of 
water and dissolved substances from the soil to the leaves. 
Here some of the water evaporates leaving an accumula- 
tion of salts to be used in conjunction with the carbonic 
acid gas for producing such substances as protoplasm 
and starch. A number of chemical elements, or com- 
ponent parts of salts, so-called, are required by the plant. 
The most of these are usually present in sufficient amount 
even in our worn-out soils, but continuous cropping has 
depleted the supply of others to such an extent that it has 
become necessary to add them to the soil before a maxi- 
mum crop can be grown. 
You have all become familiar with the names of the in- 
gredients, nitrogen, phosphoric acid and potash, which 
are most frequently lacking in an available form in our 
older soils. Here then lies the food problem as far as 
concerns plants. We search far and wide for these three 
ingredients, bringing nitrogen from Chili, potash from 
Cermany and phosphoric acid from our southern States. 
We endeavor to choose the form most readily assimilable 
after being mixed with the soil, and the proper mixtures 
to apply. Nitrogen is the most expensive ingredient of 
plant food, and when we consider its price, about 20 cents 
per pound, it is plain that the success or failure of farm- 
ing operations may depend upon our judgment in the se- 
lection and use of materials containing this element. 
