He bases his work upon the theory that the best and only true test for the presence of life in matter is the response of matter to external stimulus. Proceeding from this fundamental theory he has proven by in-numerable experiments that so-called inorganic matter, minerals, metals, etc., give a response to such stimulus, which response is similar, if not identical, to the response of the matter composing the bodies of plants, animals, men. He devised delicate apparatus for the measurement of the response to the outside stimulus, the degree, and other evidence being recorded in traces on a revolving cylinder. The tracings or curves obtained from tin and other metals, when compared with those obtained from living muscle, were found to be identical. He used a galvanometer, a very delicate and accurate scientific instrument, in his experiments. This instrument is so finely adjusted that the faintest current will cause a deflection of the registering needle, which is delicately swung on a tiny pivot. If the galvanometer be attached to a human nerve, and the end of the nerve be irritated, the needle will register. Prof. Bose found that when he attached the galvanometer to bars of various metals they gave a similar response when struck or twisted. The greater the irritation applied to the metal, the greater the response registered by the instrument. The analogy between the response of the metal and that of the living muscle was startling. For instance, just as in the case of the living animal muscle or nerve matter, the response becomes fatigued, so in the case of the metal the curve registered by the needle became fainter and still fainter, as the bar became more and more fatigued by the continued irritation. And again, just after such fatigue the muscle would become rested, and would again respond actively, so would the metal when given a chance to recuperate. Tetanus due to shocks constantly repeated, was caused and recovered. Metals recorded evidences of fatigue. Drugs caused identical effects on metals and animals--some exciting; some depressing; some killing. Some poisonous chemicals killed pieces of metal, rendering them immobile and therefore incapable of registering records on the apparatus. In some cases antidotes were promptly administered, and saved the life of the metal. Prof. Bose also conducted experiments on plants in the same way. Pieces of vegetable matter were found to be capable of stimulation, fatigue, excitement, depression, poison. Mrs. Annie Besant, who witnessed some of these experiments in Calcutta, has written as follows regarding the experiments on plant life: "There is something rather pathetic in seeing the way in which the tiny spot of light which records the pulses in the plant, travels in ever weaker and weaker curves, when the plant is under the influence of poison, then falls into a final despairing straight line, and--stops. One feels as though a murder has been committed--as indeed it has."