With an extended application of his mechanical theory, Dr. Bose has
gradually removed the veil of obscurity from many a phenomenon in plant
life. The 'autonomous' movements of plants, for example, which remained
enveloped in mystery, received a satisfactory solution at his hands.
'AUTONOMOUS' MOVEMENTS
It was believed that automatically pulsating tissues draw their energy
from a mysterious "vital force" working within. By controlling external
forces, Dr. Bose stopped the pulsation and re-started it and thus
demonstrated that the 'automatic action' was not due to any internal
vital force. He pointed out that the external stimulus--instead of
causing, as was customary to suppose, an explosive chemical change and
an inevitable run-down of energy--brings about an accumulation of energy
by the plant. And with the accumulation of absorbed energy, a point is
reached when there is an overflow--the excess of energy bubbles over, as
it were, and shows itself in 'spontaneous' movements. The stimulus being
strong a single response--a single twitching of the leaflets--is not
enough to express the whole of the leaf's responsive energy and it
yields a multiple response--it reverberates--it manifests itself in
'automatic' pulsations. When, however, the accumulated energy is
exhausted, then there is also an end of 'spontaneous movements.' There
are strictly speaking, no 'spontaneous' movements; those known by that
name are really due either to the immediate effects of external stimulus
or to the stimulus previously absorbed and held latent in the plant to
find subsequent expression--due to the direct or indirect action of
external forces which are transformed in the machinery of the plants in
obedience to the principle of the Conservation of Energy.
"ASCENT OF SAP" "AND GROWTH"
Dr. Bose then showed that, not gross mechanical movements alone, but
also other invisible movements are initiated by the action of stimulus,
and that the various activities, such as the "ascent of sap" and
"growth" are in reality different reactions to the stimulating action of
energy supplied by the environment. In this way, Dr. Bose showed that
several obscure phenomena, in the life-processes of the plant, can be
very satisfactorily explained by the Mechanical Theory.
It would not be out of place to mention that Dr. Bose, to carry on his
researches on the Ascent of Sap, invented a new type of instrument
(Shoshungraph). And for an accurate investigation on the phenomenon of
growth of plants he devised an instrument (Growth Recorder) for
instantaneous measurement of the rate of growth and another instrument
(Balanced Crescograph) for determining the influences of various
agencies on growth. So very marvellous these instruments that the
growth, which takes place, during a few beats of pendulum, is measured,
and, in less than a quarter of an hour, the action of fertilizers,
foods, electrical currents and various stimulants are determined. "What
is the tale of Aladdin and his wonderful lamp" exclaims the Editor of
the _Scientific American_ "compared with the true story told by the
crescograph?... Instead of waiting a whole season, perhaps years, to
discover whether or not it is wise to mix this or that fertilizer with
the soil one can now find in a few minutes!" Yet these are the
instruments which are better known in Washington than in Calcutta! The
question of their application to practical agriculture has excited more
interest in the United States of America than in this unfortunate land,
which is an essentially agricultural country!