A. After 24 hours in | B. After 24 hours in | C. After 24 hours in water | chloroform water | mercuric chloride | | [All leaves standing up | [Leaves began to | [Leaves began to droop and fresh--aphides | droop in 1 hour | in 4 hours. Deep alive] | and bent over in | discolouration along | 3 hours--aphides | the veins. Aphides | dead] | dead] | | Electric | Electric | Electric Response | response | response (1) 21 dns. | (1) 1 dn. | (1) 0 dn. (2) 31 " | (2) 1 " | (2) .25 " (3) 26 " | (3) 2 " | (3) .25 " (4) 15 " | (4) 0 " | (4) 0 " (5) 17 " | (5) 1 " | (5) .25 " (6) 23 " | (6) 1.5 " | (6) .25 " (7) 30 " | (7) 2 " | (7) 0 " (8) 27 " | (8) 1 " | (8) .25 " (9) 29 " | (9) 1 " | (9) .25 " (10) 17 " | (10) .5 " | (10) .5 " ------------------------+----------------------+----------------------- Mean response 23.6 | Mean 1 | Mean .15 II. LEAF-STALK OF HORSE-CHESTNUT (1) 15 dns. | (1) .5 dn. | (1) 0 dn. (2) 17 " | (2) .5 " | (2) 0 " (3) 10 " | (3) 0 " | (3) 0 " ------------------------+----------------------+----------------------- Mean 14 | Mean .3 | Mean 0 These results conclusively prove the physiological nature of the response. I shall in a succeeding chapter give a continuous series of response-curves showing how, owing to progressive death from the action of poison, the responses undergo steady diminution till they are completely abolished. #Effect of high temperature.#--It is well known that plants are killed when subjected to high temperatures. I took a stalk, and, using the block method, with torsional vibration as the stimulus, obtained strong responses at both ends A and B. I then immersed the same stalk for a short time in hot water at about 65 deg. C., and again stimulated it as before. But at neither A nor B could any response now be evoked. As all the external conditions were the same in the first and second parts of this experiment, the only difference being that in one the stalk was alive and in the other killed, we have here further and conclusive proof of the physiological character of electric response in plants.