12 PLANT LIFE ON THE FARM. 
Protoplasm—Cells.—The raw material (the term is not 
quite accurate, but for illustration sake it may pass) is 
that very marvellous substance now called ‘ protoplasm.” 
We must leave it to chemists and microscopists to ex- 
plain its composition and indicate its appearance, Suffice 
it here to call it, as Huxley did, ‘‘the physical basis of 
life.” Without it, or when it is dead, the plant is dead 
too; with it the plant lives, without it it dies. Itisa 
viscid, colorless, jelly-like ‘substance, endowed with all 
those varied properties which constitute in the aggregate 
all that we can tangibly realize of the manifestations of 
life. 
With few exceptions, which it is not necessary here to 
particularize, the protoplasm does not exist in one un- 
broken mass, but is contained in little membranous bags 
called ‘‘ cells.” These cells are of various shapes and 
sizes, and may undergo various modifications during the 
growth of the plant. They are large enough to be seen 
by the naked eye in the pulp of an orange, but usually 
they require the aid of the microscope to discern them. 
They are lengthened into tubes placed end to end to form 
conduits, or thickened into fibres. The cells, then, vari- 
ously combined and modified, constitute what we have 
termed the fabric of the plant. ach living cell consists 
essentially of a certain proportion of protoplasm contained 
within a membranous bag or bladder, called technically 
the “‘cell-wall.” There may be, and generally are, other 
things besides the protoplasm within the cell-wall, such, 
for instance, as a small ovoid body known as the “ nu- 
cleus,” and green coloring matter or ‘chlorophyll ;” but 
these other things, important as they are, we may leave 
out of consideration for the present. 
_ Every plant and every part of every plant is made up 
of cells such as have been mentioned. As a cell a plant 
begins its independent life; with and by cells it lives, 
grows, multiplies; by their decay it dies. It is, as has 
