The Soul of Plants
Plant Autographs and their Revelations. By Sir J. C. Bose. (Longmans. 7s. 6d.) VANIILIAR. ideas are taken for granted. They are axioms ; they are instruments of thought ; they are the well-worn rhannels along which all our thinking naturally runs. ' To abandon long-accepted axioms, to divert our thinking from t he Old into new channels is difficult, is even, when the axioms have been accepted too long and the old channels have worn theniSelves.tOo deep, an impossibility. The aged are necessarily I he most orthodox.
Notions which clash with our accepted axioms tend to strike us either as outrageous or as absurd. We are outraged if the new notions concern our more intimate and human ortho- doxies. What we believe about ourselves is sacred ; doctrines which fail to harmonize with our beliefs seem immoral or sacrilegious, until, in due course, they become the sacred commonplaces of another generation. What we believe about the non-human universe is less sacred. Consequently, heresies in the non-human sphere are only absurd and comic, not wicked. Thus, in its day, Darwinism seemed outrageous ; established religion and men's most cherished beliefs about human origins and destinies were affected by the new, theory. Non-Euclidean geometries, on the other hand, being remote from human interests, seemed merely ab- surd.
Sir J. C. Bose's researches have led him to theoretical conclusions which, in another age, would probably have seemed obvious. Our ancestors found no difficulty in believing that all objects were alive, or might, at any rate, in certain circumstances be animated. What they found hard to swallow was the notion that anything was completely dead. Our axioms are different from theirs, and what seemed obvious to them seems absurd to us. When someone tells us that minerals feel fatigue and that their responses to the outside world are affected by poisons and stimulants in exactly the same way as are the responses of living organisms, we are incredulous ; the thing seems preposterous. Our first reaction to an account of Bose's experiments on metals, of Warburg's work on the respiration of charcoal, is an access of scepticism. The ideas with which we have been brought up are too strong for us.
And yet, when one comes to think of it, there is nothing inherently absurd about the notion that dead matter should possess some of the attributes of living matter. Dead stuff and living stuff are Made of the same constituents, obey the Name physical laws. And unless we believe that life and con- sciousness were suddenly and by a miracle introduced into the world from outside, we must logically suppose that the smallest Particles of inanimate matter hold within themselves the potentialities of life and awareness. The lifelike behaviour of dead matter ought not to surprise us. It would be much bore surprising if its behaviour were quite unlifelike.
It is the same within the world of life. Having been brought np with certain ideas, we are astonished, we feel sceptical, When Sir J. C. Bose tells us that plants have a nervous system similar to that of animals and pulsating tissues corresponding to the heart. And yet, after all, there is nothing to be amazed tit in the discovery that different kinds of organisms solve the ',tone vital problems in the same sort of way. Animals and Plants have evolved widely different methods of nutrition ; hut they have solved the problem 9f reproduction in funda- mentally the same way. Both are faced with the problems of transferring vital fluids and sending signals from one part of the organism to another. These problems .may be solved m the same way, or they may not. Sir J. C. Bose tells us that they have been solved in the same way. There is no a priori reason for being sceptical. One must examine his evidence. - That ,Bose's conclusions have not been long anticipated is due to technical difficulties which he has overcome. The movements of plants are in most eases too small to be detected with the naked eye or even with the microscope. Bose has iavented a number of extremely ingenious and delicate
machines, with the aid of which the plant's infinitesimal move- ments can be visibly recorded. Thus, the existence of the plant's " heart " has been demonstrated by direct mechanical methods and again by electrical methods. By means of the latter he has been able to localize the "heart "—in other words, to show precisely which is the layer of tissue that pul- sates. The activity of this pulsating tissue can be heightened by stimulants, depressed by narcotics and completely arrested by poisons. I shall never forget, at the Bose Institute in Calcutta, the really horrifying spectacle of a plant being murdered by an overdose of chloroform. Every phase of the death struggle was recorded by the moving needle—the momentary stimulation, the depression, the irregular spas- modic beatings of the "heart," the final spasm and then complete inactivity, death. That something does pulsate inside a plant there is no question. It remains to be decided whether this layer of throbbing tissue fulfils the function of a heart. Sir J. C. Bose is of opinion that it does and that the rise of sap in trees (hitherto never adequately explained) is due to the action of the pulsating tissue—aided, no doubt, by the suction exercised by the leaves and to some extent by osmosis. I am quite incompetent to say whether he is right or wrong. If it is a heart, then it is a surprisingly feeble one ; for its systole and diastole arc measured in millionths of an inch. One wonders how such delicate pumping can be effective.
By means of his apparatus, Bose has shown that all plants are sensitive and respond to stimuli, though in a vastly less striking fashion than do the mimosas and other recognized Sensitive Plants. The responses of the ordinary plant have to be enormously magnified before they can be detected. The question arises how stimuli are transferred from one part of the plant to another. Bose claims to have discovered something closely corresponding to the nervous system of the lower animals.
There are many other matters of interest in this book. The chapters on plant growth (which Bose has measured, second by second, with a machine capable of magnifying a movement by literally millions of times) arc particularly fascinating. One is astonished by the promptitude and completeness with which living vegetable matter responds to the minutest changes in the environment. The finer the perceiving instru- ment, the more amazing is the thing perceived found to be. Bose has given us new eyes to look at the world of living things ; we owe him a debt of gratitude.
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