104 SUMMARY OF CUREENT RESEARCHES BELATING TO 



yet no harm seemed to arise from this comj)ouncl when added within 

 certain limits ; consequently, as the hydroxide formed by double 

 decomposition lies within these limits, it is concluded that it exercises 

 no influence. 



Movement of Water in Plants.* — To determine the relative in- 

 fluence of transpiration and of " root-pressure " (osmosis from cell to 

 cell) in causing the ascent of sap, Miss G. E. Cooley made a number 

 of experiments with the manometer on Bohinia pseudacacia, with the 

 following results : — The influence of transpiration is felt in very 

 remote parts of the plant ; and, in this case at least, root-pressure 

 has but little influence in supplying the wants created by transpira- 

 tion. 



Conduction of Water. f— Dr. F- G. Kohl describes an apparatus 

 by which he claims to have proved, as the result of a number of 

 experiments, that (1) The bending of a shoot causes the cell-cavities 

 to become less, but does not completely close them for the passage 

 of water ; (2) The continuity of the current of water is not inter- 

 rupted by the bending of a shoot ; and (3) It is possible by alternate 

 increase and diminution of the diameter of the vessels or tracheids of a 

 shoot, to increase or diminish the current of water, the conditions of 

 transpiration remaining the same ; and that a complete closing of 

 the cell-cavities altogether suppresses the transpiration-current. 



Conduction of Sap through the Roots4— As the result of the 

 present state of our knowledge, Herr C Kraus states that it is 

 most probable that in all plants, even woody plants, the water absorbed 

 from without is forced up a certain height in the wood by pressure. 

 There is very often no bleeding from the woody portion of a cauline 

 organ which does not root, although this might be expected from the 

 structure and arrangement of the j)arenchyma. The normal sap 

 which exudes from the root when wounded is very thin, while that 

 which exudes from the stem contains a relatively much larger quantity 

 of substances in solution. 



Galvanotropism. § — Herr J. Brunchorst contests that theory of 

 Rischawi || that galvauotropic curvatures depend only on a direct 

 cataphoric current; he considers, on the other hand, that at all events 

 positive curvatures depeud to a large extent on the substance elimi- 

 nated at the positive electrode ; negative cmwatures are possibly not 

 to be regarded as truly galvauotropic. 



Variations of Transpiration.^— By a series of experiments on 

 the seeds of peas and haricots, M. J. Vesque has come to the con- 

 clusion that, while nocturnal transpiration is at first less than diurnal, 



* Canadian Kecord of Science, i. (1885) pp. 202-7. 



t Bot. Ztg., xliii. (1885) pp. 522-6. 



j Forsch. a. d. Geb. der Agiiculturphysik, viii. (1885) pp. 33-50. See Bot. 

 Centralbl., xxiii. (1885) p. 69. See this Journal, iv. (1884) p. 591, v. (1885) 

 p. 837. 



§ Bot. Centralbl., xxiii. (1885) pp. 192-8. 



II Sec this Journal, v. (1885) p. 1032. 



i; Ann. Agronoini(iuc.s, x. (1884) pp. 113-25. See Bulh Soc. Bot. France, 

 xxxii. (1885). Ecv. Bibl., p. 101. 



