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Anatomy of the Cell. The cell is of varying shape and size in accord-
ance with its specialized function or location, It is bounded by a
protoplasmic film called the plasma membrane and it may have a non-
protoplasmic, true membrane or wall. Contained within the membrane
are the two important parts of the cell-=cytosome and nucleus.

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Protoplasm is that peculiar material which possesses the properties
the sum total of which is L-I-F-E. Chemically it is a complex mix
ture of proteins, lipoids or fatty bodies, carbohydrates, inorganic
salts, and water. Physically it displays the properties of a com-
plex colloidal system and behaves as a viscid liquid, sometimes
colored, but often practically colorless. The cytosome and nucleus
are composed of various kinds of protoplasm.

"Cytoplasm" and "nucleoplasm" express this fact.

Cytosome

Within this protoplasm (cytoplasm) are a number of organized, visible
structures some of which participate in cell division while others
are either formed anew by each cell or are inclusion bodies only.

Nucleus is usually surrounded by the cytosome and varies in shape.
It always contains a peculiar protein material known as chromatin
believed to be the specialized vehicle which transmits hereditary

characteristics.
(1) Chremosomes. Within the nucleus the tiny granules of chromatin

(2)

are arranged in units called chromosomes. These are the units
of mechanism for the transmission of life in accordance with
the laws of heredity.

 

Function and Number of Chromosomes. The ¢ells of various
species have a characteristic and fixed number and variety
of chromosomes. This number is spoken of as "diploid."
The human fertilized ovum has 48 and every resultant cell
has 48 chromosomes.

When a new individual is to appear, the germ cell of each
parent loses one half of its chromosomes and contributes the
other half to the union. By this means heredity goes back
through the ages to the beginning of life.

Physiology of Cells.

"Physiologically, we note that, in general, all cells exhibit
(a) synthetic functions, that is, anabolic or constructive
functions, that are performed chiefly by or because of the
nucleus; and (b) dissociative functions, that is to say,
destructive or katabolic functions that are performed chiefly
by the cytoplasme Thus the nucleus is chiefly an organ of
growth, construction, repair, reproduction, and heredity.

The cytoplasm is chiefly an organ of power-production and
dynamic service through energy transformations."=-Thomas A.
Storey "Principles of Hygiene."