In Chapter X of Response in the Living and Non-Living, Bose puts one sentence in italics, and that sentence tips the whole book over: “We shall use the same apparatus and the same mode of stimulation as those employed in obtaining plant response, merely substituting, for the stalk of a plant, a metallic wire, say ‘tin'”. He has just spent nine chapters gripping celery, cauliflower and turnip petioles in the middle of a clamp, applying a calibrated twist to them, reading off the galvanometer the small drop in potential that follows. He takes the stalk out. He puts an annealed tin wire in its place. And the wire responds.
That is what this 1902 book contains, and it has to be said straight away to head off the misunderstanding that clings to it: this is not a book about the sensitivity of plants. It is a 193-page electrophysiology monograph, more than a hundred and seventeen figures, written by a physicist at Presidency College in Calcutta, completed at the Davy-Faraday Laboratory of the Royal Institution in May 1902, and meant to demolish one precise notion, the vital force.
What the volume contains
Twenty chapters, in three very unequal movements. The animal first, only two chapters, which serve as a methodological yardstick. Then the plant, seven chapters, III to IX. Then metal, nine chapters, X to XVI. Then three chapters on light and vision, and a comparative recapitulation that sets the three kingdoms side by side.
Each chapter opens with a one-sentence summary in dashes, listing its points, and unfolds in subsections announced by a word in bold. You move through it as you would through a catalogue. At the head of the volume, the epigraph from the Rig Veda, “The real is one: wise men call it variously”, and a three-word dedication, “To my Countrymen”. Along with the closing Turkish bath comparison, those are just about the only literary excursions in the book.
One clarification that matters. The crescograph is not in this book. A full-text search of the 1902 edition: not one occurrence, and none of the word Mimosa either. The instrument that magnifies growth up to ten thousand times comes afterwards, in Bose’s later works. Here we are not measuring growth, we are measuring variations of potential under mechanical, thermal, chemical or light stimulus. Crediting this volume with the crescograph is a widespread error.
The instruments, which are the real subject
Bose does not theorise first, he builds. An aperiodic D’Arsonval whose exact constants he gives, a period of eleven seconds, one thousand-millionth of an ampere for one millimetre of deflection at one metre. A clockwork drum on which a stylograph follows the light spot by hand, or else a photographic plate where the spot writes its own curve, in white on a black ground.
Then the two instruments that show how demanding he is. The spring tapper grows out of a tiny and formidable observation: “No two taps given by the hand can be made exactly alike.” So he needs a toothed wheel whose every spoke lifts and releases a spring, with a height of lift read off a graduated scale. Drawback: the point struck ends up damaged. Hence the torsional vibrator, where the petiole is clamped at its middle and twisted a quarter turn by a handle, the amplitude read off a graduated circle. Bose demonstrates that the two modes are equivalent, then discovers a second factor, abruptness: at a constant thirty degrees of amplitude, four speeds of torsion give four increasing responses.
And above all, the book’s own invention, the block method. The physiology of the day obtained its signal by damaging one end of the tissue, which created a current of injury. Bose refuses the wound: he simply clamps the stalk between the two contacts, the disturbance no longer passes, the action current appears. Decisive advantage, every result can be checked by its own inverse, by stimulating the other end and watching the galvanometer swing the other way.
Ordinary plants, in figures
Bose works on carrot, radish, turnip, celery, cauliflower, horse chestnut, Eucharis lily, eggplant. No sensitive plant at all, and that is deliberate. He notes that each species has its season of maximum sensitivity, carrots in August and September, radishes in early November.
The orders of magnitude. On turnip, a resting potential of 0.13 volt, which a sharp tap makes fall by 0.026 volt, and a stronger tap by 0.047 volt. After a sudden frost, the response of radishes drops from 0.075 volt to 0.003 volt, one twenty-fifth. Some revive in water at 20 °C, others do not, and Bose concludes that the former were numbed and the latter dead. The death point by hot bath lies between 53 and 55 °C, one specimen going from 160 divisions at 17 °C to a single division at 53 °C. Just before dying, the response does not fade out: it reverses.
Fatigue takes up a whole chapter, and Bose is very acute on it. A radish stimulated every minute for half an hour shows “not the least variation”. Go to thirty seconds and the responses collapse at once, come back to the minute and they climb again. His explanation is not metabolic, it is mechanical: fatigue is residual strain, tissue that has not finished returning to equilibrium when the next stimulus lands.
Then comes the decisive test of the day, that of anaesthetics and poisons, supposed to separate the vital from the non-vital. Ten plane tree petioles in water, ten in chloroformed water, ten in five per cent mercuric chloride, twenty-four hours. Mean responses: 23.6 divisions, 1 division, 0.15 division. In passing, an observation I find overwhelming in its sharpness of eye, noted without comment in the middle of the tables: “The aphides feeding on the leaves died even before the appearance of the discoloured patches.” The aphids die before the leaf even loses its colour.
Then Bose records continuously, blows chloroform vapour into a glass chamber, and is himself surprised by the speed: “It was a surprise to me to find that, with good specimens, the effect was manifested in the course of so short a time as a minute or so.” He anticipates the critic’s objection, which would be that the reagent changes the resistance of the tissue and not the electromotive force, and he answers it with a circuit, a megohm in series that makes the twenty thousand ohms of the carrot negligible.
The metal that fatigues
This is half the book, and this is what caused the scandal. Platinum fatigues markedly. Tin is almost indefatigable, but Bose ends up obtaining its fatigue curve and notes soberly: “Nothing is absolutely indefatigable.” He repeats on the wire the rhythm experiment done on the radish, one minute then thirty seconds then one minute again, and finds exactly the same fall followed by exactly the same restoration. He obtains the staircase effect of heart muscle, and the reversed responses of a stale nerve.
His argument is there, and it is strong: “the various typical fatigue effects exhibited in living substances are exactly reproduced in metals, where there can be question neither of fatigue-product producing fatigue effects, nor of those constructive processes by which they might be removed”. In other words, metal has neither waste products nor any restorative metabolism, and yet it fatigues and recovers. The explanation by fatigue toxins collapses.
The reagents complete the picture. Sodium carbonate stimulates tin. Oxalic acid abolishes it, at one part in ten thousand. Bose then takes the wire out, wipes it under a trickle of water until every trace of acid is gone, puts it back in place: it no longer responds, and rubbing with emery cloth does not always revive it. By dosing more finely, he obtains what he calls a molecular arrest, recovery going from one minute to five, then not coming back at all, “as if the molecular mechanism became, as it were, clogged or locked up”. And the dose effect, exactly the reverse of the plant’s: potash at three per thousand excites tin, at three per cent it kills it.
The last three chapters, on the silver bromide cell that gives eight thousandths of a volt under a minute of illumination, and on the after-images of human vision, are the boldest and the most dated. In them Bose writes that “the eye is practically a photo-electric cell”, and sets his silver plate alongside Waller’s frog retina. That is where the book overreaches most.
The thesis, and what it aims at
Bose never writes that metal is alive. He writes that the criterion by which the living was supposed to be separated from the rest separates nothing, since the tin wire passes it. His target is named, it is vitalism, which he attacks by quoting Verworn on that vital force used “in a wholly mystical form as a convenient explanation of all sorts of vital phenomena”. His last sentence, before the index, speaks of laws that know no change, acting equally and uniformly throughout the organic and inorganic worlds.
So this is the opposite of a mystical book. The word Bose uses is irritability, in the technical sense of capacity to respond. He speaks neither of emotion nor of plant consciousness, and a reader who came here looking for a plant that feels will find a physicist demonstrating that a platinum wire fatigues. His language is late Victorian scientific English, very clear but dense with terms he sometimes coins himself, zincoid, cuproid, iso-electric, diphasic. Chapters XII to XV are technical and frankly repetitive. Chapters I to IV and XX are enough for anyone who wants the thesis.
A word on the reception, because there is something to learn from it. Burdon-Sanderson’s main grievance, in 1901, was not experimental, it was lexical: Bose wrote response where in his view he should have written reaction, the first word granting too much initiative to the plant. That is exactly the reproach levelled at plant neurobiology a hundred and six years later. Waller asked for the rejection of the manuscript submitted to the Royal Society. The paper read on 6 June 1901 was never published. And yet, in 1992, an article in Nature established that a wounded tomato triggers its defences by electrical signal, phloem blocked or not. Bose was right, ninety years earlier, on the very point he was refused permission to print.
On metals, by contrast, nothing has confirmed his extension, and that has to be said just as plainly.
There are two French translations of Bose from Gauthier-Villars, Poincaré’s publisher, which places the book on the hard science shelf and not among the curiosities. This one (Réactions de la matière vivante et non vivante) is by Édouard Monod-Herzen, 1926. The quotations above are given in the English of 1902.
What I kept from it, for my part, comes down to a few words. Bose took ten years to build the instrument before stating the thesis, and he spent half his pages answering objections in advance, circuit by circuit. The gesture comes before the idea. That is an order I have never let go of.
Read in October 2016. Note written in 2026.
