The Views Of Botanists Illustrated

It might have been expected that in the domain of plant-biology, if

anywhere, the mechanistic standpoint would have been the prevailing one.

For it is almost a matter of course to regard plants as devoid of

sensation or "psychical" life, and as mechanical systems, chemical

laboratories, and reflex mechanisms, and this way of regarding them has

been made easy by the very marked uniformity and lack of spontaneity in

vital processes as compared with those of animals. But it is not the

case that mechanical theories have here prevailed. The opposition to them

is just as great here as elsewhere, and from the days of Wigand onwards it

has been almost continuously sustained.(88) Very characteristic is

Pfeffer's "Pflanzen-Physiologie" (1897), which is written professedly from

the mechanist point of view. "Vitalism," according to this authority, is

to be rejected, but instead of "vital force" he offers us "given

properties," and the alleged machine-like collocations of the most minute

elements. In regard, for instance, to the riddle of development and

morphogenesis, we must simply accept it as a "given property," that the

acorn grows in an oak and nothing else. The chemical explanation of the

vital functions of protoplasm is also to be rejected; as a shattered watch

is no longer a watch though it remains chemically the same, so it is with

protoplasm. The available chemical knowledge of the substances of which

protoplasm is made up is insufficient to render the vital processes

intelligible. Here, as everywhere else, we have to reckon with ultimate

"properties (entities), which we neither can, nor desire to analyse

further." "The human mind is no more capable of forming a conception of

the ultimate cause of things than of eternity." If all the views here

indicated were followed out to their logical conclusions, they would

hinder rather than further the process of reduction to terms of

physico-chemical sequences.

Kerner von Marilaun in his "Pflanzenleben" deliberately takes up a

thorough-going vitalist position, and on this point as well as on many

others he opposed the current theory of the school (Darwinism). It is

true, he admits, that many of the phenomena in plants can be explained in

purely mechanical terms, but they are only those which may occur also in

non-living structures. The specific expressions of life cannot be

explained in this way. He shows this more fully in regard to the most

fundamental of all the vital processes in the plant-body--the breaking up

of carbonic acid gas by the chlorophyll to obtain the carbon which is the

fundamental element in all living organisms. We know the requisite

conditions: the supply of raw material, and the sunlight from which the

energy is derived. But how the chlorophyll makes use of these to effect

the breaking up, and how it starts the subsequent syntheses of the carbon

into the most complex organic compounds remains a mystery. And so on

upwards through all the strictly vital phenomena.

Wiesner's(89) view of things is essentially similar. He gives a very

impressive picture of the mystery of the chemistry of the plant, showing

how small is the number of food-stuffs and raw materials in comparison to

the thousands of highly complex chemical substances which the plant

produces, and how much work there is involved in de-oxydising the food and

in forming syntheses. He, too, refuses, as usual, to postulate "vital

force." Yet to speak of "the fundamental peculiarities of the living

matter inherent in the organism" and to admit that plants are "irritable,"

"heliotropic," "geotropic," &c., amounts to much the same thing as

postulating vital force; that is to say, to a mere naming of the specific

problem of life without explaining it. The author himself admits this when

he says in another place: "If I compare organisms with inorganic systems,

I find that the progress of our knowledge is continually enlarging the

gulf which separates the one from the other!"

These anti-mechanical tendencies show themselves most emphatically in the

work of Fr. Ludwig.(90) In his concluding chapter, after a discussion of

the theories of Darwin, Naegeli, and Weismann, he postulates, for

variation, heredity, and species-formation in particular, "forces other

than physico-chemical," "let us call them frankly psychical."

It is instructive to see how these "vitalistic" views crop up even in

studies of detail and of the microscopically small, as for instance in E.

Crato's "Beitraege zur Anatomie und Physiologie des Elementar-organismus."

How the living organism contains within itself what is in its turn living,

down into ever smaller detail, (amoeboid movements of certain plastines,

physodes,) how incomparable the living organism is with a "machine," to

which its libellers are so fond of likening it, how it builds itself up,

steers, and stokes itself, how it produces with "playful ease" the most

marvellous and graceful forms, makes combinations and breaks them up, how

analogous its whole activity is to "being able" and "willing," all this is

clearly brought out.(91)

A very fresh and lucid presentation of the whole case is given by Borodin,

Professor of Botany in St. Petersburg, in his essay, "Protoplasm and Vital

Force."(92) He sharply castigates the one-sidedness and impetuosity of the

mechanical theory, as in Haeckel's discovery of Bathybius and of

non-nucleated bacteria. The latter are problematical, and the former has

been proved an illusion. To penetrate farther into the processes of life

is simply to become aware of an ever-deepening series of riddles. There is

no such thing as "protoplasm," or "living proteid," or indeed any unified,

simple "living matter" whatever. Artificial "oil-emulsion amoebae"(93) bear

the same relation to living ones that Vaucanson's mechanical duck bears to

a real one; that is, none at all. Our "protoplasm" is as mystical as the

old "vital force," and both are only camping-grounds for our ignorance.

Neither the mechanical nor the atomic theory were the results of exact

investigations; they were borrowed from philosophy. We do indeed

investigate the typically vital process of irritability by physical

methods. But the response made by the organism to physical coercion may be

called a mockery of physics. The mechanists help themselves out with crude

analogies from the mechanical, conceal the problem with the name

"irritability," and thus get rid of the greatest marvels. If vital force

itself were to call out from its cells, "Here I am," they would probably

see in it only a remarkable case of "irritability." Mechanism is no more

positive knowledge than vitalism is; it is only the dogmatic faith of the

majority of present-day naturalists.