Dr. Bose showed that there is no physiological response given by the
most highly organised animal tissue that is not also to be met with in
the plant. He carried on "Researches on Diurnal Sleep" and showed that
the plant is not equally sensitive to an external stimulus during day
and night, and that there is a fundamental identity of life-reaction in
plant and animal, as seen in a similar periodic insensibility in both,
corresponding to what we call _sleep_. He also showed that the passage
of life in the plant, as in the animal, is marked by an unmistakable
spasm. He invented, an instrument (Morograph) with which he recorded the
critical point of death of a plant with great exactness. He
demonstrated, in the most conclusive manner, that there is an essential
unity of physiological effects of drugs on plant and animal tissues and
showed the modifications which are introduced into these effects by the
factor of individual 'constitution.' It may be mentioned casually that
"this physiological identity in the effect of drugs is regarded by
leading physicians as of great significance in the scientific advance of
Medicine; since we have a means of testing the effect of drugs under
conditions far simpler than those presented by the patient, far subtler
too, as well as more humane than those of experiments on animals."[19]
Dr. Bose further demonstrated that there is conduction of the excitatory
impulse in the plant, like the nervous impulse in the animal; and showed
the possibility of detecting the wave in transit and measured the speed
with which the excitation coursed through the plant and also showed that
the velocity of excitation is modified, by different agencies, even in
the case of ordinary plants. He also showed that the polar effects
induced by electric currents, both in plants and animals, are identical.
These remarkable researches on Plant Response have 'revolutionised in
some respects and very much extended in others our knowledge of the
response of plants to stimulus.'