1909.] NATURAL SCIENCES OF PHILADELPHIA 67 



and leafy portion was found to remain turgid for a few days. Another 

 experiment, which was held to negative the theory of protoplasmic 

 activity, was that in which boiling water was poured on the root, when 

 the plant continued to respire in spite of the roots having been killed. 

 These experiments of Strasburger are negatived by the experiments 

 with the twigs in the various chemical solutions previously described. 

 As before indicated, the response of the twigs in the most susceptible 

 instance did not take place until a week after the twigs were placed 

 in the chemical solutions. After the first response, the opening of. the 

 buds progressed steadily until the leaves had fully expanded. In 

 some instances the branch grew considerably in length after the open- 

 ing of the buds had started. As the experimental data prove, many 

 twigs did not respond but were killed outright, as illustrated by the 

 twigs of the Carolina poplar, Populus monilifera, in the ten-drop hydro- 

 chloric acid solution, or as in the case of Quercus palustris in the sodium 

 bicarbonate, sodium chloride and ammonium hydrate. Many twigs 

 which responded at first by the enlargement or even bursting of the 

 buds afterwards made no advance and were eventually killed, and 

 ultimately most of the twigs not in water, but with their ends immersed 

 in the chemical solutions, died after the buds had dried up or the 

 leaves had wilted. This seems to indicate that the chemicals first 

 acted as a stimulus on the twigs; this was followed by the ascent of 

 water, by the suctional activity of the living cells of the twig and bud, 

 while the poisons lagged behind. As long as any of the cells remained 

 alive in the upper part of the twigs and in the buds they maintained 

 their suctional activity. Bose, 2 by a series of elaborate and pains- 

 taking experiments, has shown after the administration of a poison 

 at the cut end of a branch or petiole that successive zones are killed 

 one after another, and that the death of a point below does not stop the 

 suction above. He says: "It is evident that the application of poison 

 at the root or cut end of a stem does not in general arrest suction until 

 the whole plant is killed." The records of his newly devised shoshun- 

 graph indicate that the final arrest occurs after an appropriately long- 

 period. That a poison can easily pass through killed tissue owing to 

 the suctional response of cells higher up, Bose proved in his experi- 

 ments on Desmodium, when he placed the cut end of a petiole in copper 

 sulphate solution. In this case there are areas which during the 

 ascent of the poison react visibly by the motile indications of the 



2 Bose, Jagadis Chunder, Plant Response as a Means of Physiological Investi- 

 gation, 1906, p. 385. 



