ORGANIZATION AND CHEMICAL COMPOSITION OF LIVING AND BRUTE MATTER.
Laws of the organization and of the chemical composition of living
beings—Relative value of these laws; vital phenomena in crushed
protoplasm—Vital phenomena in brute bodies.
_Enumeration of the Principal Characters of Living Beings._—The
programme which we have just sketched compels us to look in the brute
being for the properties of living beings. What, then, are, in fact,
the characteristics of an authentic, complete, living being? What are
its fundamental properties? We have enumerated them above as follows:—A
certain chemical composition, which is that of living matter; a
structure or organization; a specific form; an evolution which has a
duration, that of life, and an end, death; a property of growth or
nutrition; a property of reproduction. Which of these characters counts
for most in the definition of life? Are they all equally necessary? If
some of them were wanting, would that justify the transference of a
being, who might possess the rest, from the animate world to that of
minerals? This is precisely the question that is under consideration.
_Organization and Chemical Composition of Living Beings._—All that we
know concerning the constitution of living matter and its organization
is summed up in the laws of the _chemical unity_ and the _morphological
unity of living beings_ (v. Book III.). These laws seem to be a
legitimate generalization from all the facts observed. The first
states that the phenomena of life are manifested only in and through
living matter, protoplasm—_i.e._, in and through a substance which
has a certain chemical and physical composition. Chemically it is a
proteid complexus with a hexonic nucleus. Physically it shows a frothy
structure analogous to that resulting from the mixture of two granular,
immiscible liquids, of different viscosities. The second law states
that the phenomena of life can only be maintained in a protoplasm which
has the organization of the complete cell, with its cellular body and
nucleus.
_Relative Value of these Laws. Exceptions._—What is the signification
of these laws of the chemical composition and organization of living
beings? Evidently that life in all its plenitude can only exist and be
perpetuated under their protection. If these laws were absolute, if
it were true that no life were possible but in and through albuminous
protoplasm, but in and through the cell, the problem of “the life of
matter” would be decided in the negative.
May it not happen, however, that fragmentary and incomplete vital
manifestations, progressive traces of a true life, may occur under
different conditions; for example, in matter which is not protoplasm,
and in a body which has a structure differing from that of a cell—that
is to say, in a being which would be neither animal nor plant? We must
seek the answer to this question by an appeal to experiment.
Without leaving the animal and vegetable kingdoms—_i.e._, real living
beings—we already see less rigour in the laws governing chemical
constitution and cellular organization.
Experiments in merotomy—_i.e._, in amputation—carried out on the
nervous element by Waller, on infusoria by Brandt, Gruber, Balbiani,
Nussbaum, and Verworn, show us the necessity of the presence of the
cellular body and the nucleus—_i.e._, of the integrity of the cell. But
they also teach us that when that integrity no longer exists death does
not immediately follow. A part of the vital functions continues to be
performed in denucleated protoplasm, in a cell which is mutilated and
incomplete.
_Vital Phenomena in Crushed Protoplasm._—It is true also that grinding
and crushing suppress the greater part of the functions of the cell.
But tests with pulps of various organs and with those of certain
yeasts also show that protoplasm, even though ground and disorganized,
cannot be considered as inert, and that it still exhibits many of its
characteristic phenomena; for example, the production of diastases,
the specific agents of vital chemistry. Finally, while we do not
know enough about the actions of which the secondary elements of
protoplasm—its granulations, its filaments—are capable, which this or
that method of destruction may bring to light, at least we know that
actions of this kind exist.
To sum up, we are far from being able to deny that rudimentary,
isolated vital acts may be produced by the various bodies that result
from the dismemberment of protoplasm. The integrity of the cellular
organization, even the integrity of protoplasm itself, are therefore
not indispensable for these partial manifestations of vitality.
Besides, biologists admit that there exist within the protoplasm
aliquot parts, elements of an inferior order, which possess special
activities. These secondary elements must have the principle of their
activity within themselves. Such are the _biophors_ to which Weismann
attributes the vital functions of the cell, nutrition, growth, and
multiplication. If there are biophors within the cell, we may imagine
them outside the cell, and since they carry within themselves the
principle of their activity they may exercise it in an independent
manner. Unhappily the biophors, and other constituent elements of
that kind, are purely hypothetical. They are like Darwin’s gemmules,
Altmann’s bioblasts, and the pangens of De Vries. They have no relation
to facts of observation and to real existence.
_Vital Phenomena in Brute Bodies._—There is no doubt that certain
phenomena of vitality may occur outside of the cellular atmosphere.
And carrying this further, we may admit that they may be produced in
certain slightly organized bodies (crushed cells), and then in certain
unorganized bodies in certain brute beings. In every case it is certain
that effects are produced at any rate similar to those which are
characteristic of living matter. It is for observation and experiment
to decide as to the degree of similarity, and their verdict is that the
similarity is complete. The crystals and the crystalline germs studied
by Ostwald and Tammann are the seat of phenomena which are quite
comparable to those of vitality.