146 THE MECHANISM OF ABSORPTION AND TRANSLOCATION 



Osmotic values. In column III of the table below the molecular weight of 

 each substance is given, and in column VI the weight which, when dissolved in 

 a litre of water, produces a solution isosmotic with a decinormal solution of KNO S 

 (10-1 grm. in a litre of water). This contains nearly i per cent, of KNO 8 , and 

 hence the approximate degree of concentration, necessary for a given solution to be 

 isosmotic with a i per cent, solution of KNO,, can at once be seen. Column V 

 gives the relative osmotic values, taking a ioi per cent. KNO 3 solution as unity. 



corpuscles. See also Koppen (ibid., 1895, Bd. xvi, p. 261). Wladimiroff attempted to found 

 a method upon certain peculiarities shown by bacteria (ibid., 1891, Bd. VII, p. 528), which is, 

 however, unreliable (A. Fischer, Jahrb. f. wiss. Bot., 1895, Bd. xxvn, p. 153). 



For physical methods see Ostwald, Lehrb. d. allgem. Chemie, 1891, 2. Aufl., Bd. I, p. 666. 

 By means of certain definite relationships existing between vapour tension and osmotic pressure, the 

 average turgidity existing in a tissue could be calculated in terms of osmotic value from data of 

 vapour tension. 



