In his third lecture delivered, on the 25th February 1913, at the Punjab University Hall, Dr. Bose of Calcutta dealt with "Plant Response." He said:—
In strong contrast to the energetic animal, with its various reflex movements and pulsating organs, stands the plant, in its apparent placidity and immobility. Yet that same environment which with its changing influences affects the animal is playing upon it also. Storm and sunshine, the warmth of summer and the frost of winter, drought and rain, all these come and go about it. What coercion do they exercise upon it? What subtle impress do they leave behind? These internal changes are entirely beyond our visual scrutiny. Is it possible in any way to have these revealed to us? Dr. Bose had shown the possibility of this by detecting and measuring the actual response of the organism to a questioning shock. In an excitable condition the feeblest stimulus should evoke in the plant an extraordinarily large reply in a depressed state even a strong stimulus would only call forth a feeble response; and lastly, when death overcome life, there would be an abrupt end of the power to answer to all. By the invention of different types of apparatus, the lecturer had succeeded in making the plant itself write an answering script to a testing stimulus. Scripts could also be obtained of the plant's spontaneous movements; and a recording arm demarcated the line of life from that of death.
In taking the self-made records made by the plant it was found that after the prolonged inactivity of a cold night the plant was apt to be lethargic, and its first answers indistinct. But as blow after blow was delivered, the lethargy passed off, and the replies became stronger and stronger. After the fatigue of the day, the state of things was reversed. The plant became very lethargic after excessive absorption of food; but the normal activity might be restored by artificial removal of the excess. The effect of alcohol and of various narcotics were clearly followed in the modification of the automatic record made by the plant.
A prevailing scientific error had overcome in life, there would be an abrupt end regarding a certain class of plants to be alone sensitive. The lecturer showed by certain remarkable experiments that all plants and all organs of plants were sensitive.
In certain animal tissues, a very curious phenomenon was observed. In man and other animals there were tissues which beat spontaneously. As long as life lasted, so long did the heart continue to pulsate. There could be no effect without a cause. How then was it that these pulsations became spontaneous? To this query, no satisfactory answer had been forthcoming. Similar spontaneous movements were also observable in plant tissues, and by their investigation the secret of automatism in the animal world became unravelled. The existence of these spontaneous movements could easily be demonstrated by means of the Indian "Bon Charal", the telegraph plant, whose small leaflets danced continuously up and down. The popular belief that they danced in response to the clappings of the hand was quite erroneous. From the readings of the scripts made by this plant, the lecturer was in a position to state that the automatic movements of both plants and animals were guided by laws which were identical. Thus in the rhythmic tissues of the plant and the animal the pulsation frequency was increased under the action of warmth and lessened under cold, increased frequency being attended by diminution of amplitude, and "vice versa". Under ether, there was a temporary arrest, revival being possible when the vapour was blown off. More fatal was the effect of chloroform. The most extraordinary parallelism, however, lay in the fact that those poisons which arrested the beat of the heart in a particular way arrested the plant pulsation in a corresponding manner. The lecturer had succeeded in reviving a leaflet poisoned by the application of one with a dose of counteracting poison.
A time came when after one answer to a supreme shock there was a sudden end of the plant's power to give any response. This supreme shock was the shock of death. Even in this crisis, there was no immediate change in the placid appearance of the plant. In man at the critical moment, a spasm passed through the whole body, and similarly in the plant the lecturer had discovered that a great contractile spasm took place. This was accompanied by an electrical spasm also. In the script of the death recorder the line that up to this point was being drawn became suddenly reversed, and then ended. This was the last answer of the plants.
Thus the responsiveness of the plant world was one. There was no difference of any kind between sunshine plants, and those which had hitherto been regarded as insensitive or ordinary. It had also been shown that all the varied and complex responses of the animal were foreshadowed in the plant. An impressive spectacle was thus revealed of that vast unity in which all living organisms, from the simplest plant to the highest animal, were linked together and made one.
—Amrita Bazar Patrika, 5-3-1913.
EVIDENCE BEFORE THE PUBLIC SERVICES COMMISSION
The following is the evidence given by Dr. J. C. Bose, C. S. I., C. I. E., Professor of Physics, Presidency College, Calcutta, on the 18th December, 1913, before the Royal Commission on the Public Services in India, presided over by Lord Islington, and published, in the Minutes of Evidence relating to the Education Department, at pages 135 to 137, in volume XX, Appendix to the Report of the Commissioners: