6
MARCEL FLORKIN AND HOWARD S. MASON
comparative studies of cell differentiation, was a great scientific achievement and one of the greatest in the whole history of biological sciences.
The scientific definition of organic unity in the cell theory has been
more and more determined by comparative studies and at present its
form has taken on the content which J. R. Baker has stated as follows,
in seven propositions:
"1. Most organisms contain or consist of a large number of microscopical bodies called "cells," which, in the less differentiated tissues, tend to be polyhedral or nearly spherical.
2. Cells have certain definable characters. These characters show
that cells (a) are all of essentially the same nature and (b)
are units of structure.
3. Cells always arise, directly or indirectly, from pre-existing
cells, usually by binary fission.
4. Cells sometimes become transformed into bodies no longer
possessing all the characters of cells. Cells (together with
these transformed cells, if present) are the living part of organisms: that is, the parts to which the synthesis of new material is due. Cellular organisms consist of nothing except cells,
transformed cells, and material extruded by cells and by
transformed cells (except that in some cases water, with its
dissolved substances, is taken directly from the environment
into the coelum or other intercellular spaces).
5. Cells are to some extent individuals, and there are therefore
two grades of individuality in most organisms: that of the
cells, and that of the organism as a whole.
6. Each cell of a many-celled organism corresponds in certain
respects to the whole body of a single protist.
7. Many-celled plants and animals probably originated by the
adherence of protist individuals after division." (J)
The cell theory was the origin of many studies on histological comparative data and on the nature of the cell differentiations which compose an organism. But in spite of this rapid advance of knowledge at
the level of the microscopical anatomy of organisms, the philosophical
concept of the order of nature, either when considered as a gradual
scale of organisms in a definite progression or when considered as an
equilibrium of their mutual interactions, remained in the minds of
naturalists who believed that the state under which the collection of
organisms has its raison d'etre is the very system of relations which constitute this collection. Darwin, through a new form of comparative enquiry and by considering organisms not in a herbal or museum but in
the environment in which they live, put an end to the order of nature
MARCEL FLORKIN AND HOWARD S. MASON
comparative studies of cell differentiation, was a great scientific achievement and one of the greatest in the whole history of biological sciences.
The scientific definition of organic unity in the cell theory has been
more and more determined by comparative studies and at present its
form has taken on the content which J. R. Baker has stated as follows,
in seven propositions:
"1. Most organisms contain or consist of a large number of microscopical bodies called "cells," which, in the less differentiated tissues, tend to be polyhedral or nearly spherical.
2. Cells have certain definable characters. These characters show
that cells (a) are all of essentially the same nature and (b)
are units of structure.
3. Cells always arise, directly or indirectly, from pre-existing
cells, usually by binary fission.
4. Cells sometimes become transformed into bodies no longer
possessing all the characters of cells. Cells (together with
these transformed cells, if present) are the living part of organisms: that is, the parts to which the synthesis of new material is due. Cellular organisms consist of nothing except cells,
transformed cells, and material extruded by cells and by
transformed cells (except that in some cases water, with its
dissolved substances, is taken directly from the environment
into the coelum or other intercellular spaces).
5. Cells are to some extent individuals, and there are therefore
two grades of individuality in most organisms: that of the
cells, and that of the organism as a whole.
6. Each cell of a many-celled organism corresponds in certain
respects to the whole body of a single protist.
7. Many-celled plants and animals probably originated by the
adherence of protist individuals after division." (J)
The cell theory was the origin of many studies on histological comparative data and on the nature of the cell differentiations which compose an organism. But in spite of this rapid advance of knowledge at
the level of the microscopical anatomy of organisms, the philosophical
concept of the order of nature, either when considered as a gradual
scale of organisms in a definite progression or when considered as an
equilibrium of their mutual interactions, remained in the minds of
naturalists who believed that the state under which the collection of
organisms has its raison d'etre is the very system of relations which constitute this collection. Darwin, through a new form of comparative enquiry and by considering organisms not in a herbal or museum but in
the environment in which they live, put an end to the order of nature