1918] Waynick: Antagonism and Cell Permeability 139 



He found a rapid absorption of zinc, manganese, iron, and aluminum, 

 but the total amounts taken up were small. lie gives other evidence 

 of the selective absorption of various other ions from solutions, but 

 these results are of not direct application here. It is of interest to 

 note, however, that he found a direct relation between time and ion 

 absorption. His most important conclusion, which hears directly upon 

 the problem in hand, is that strong narcosis was associated with the 

 penetration of ions in large numbers. 



Schreiner and Skinner, 13 using a similar method, have determined 

 the amounts of phosphoric acid, nitrates, and potassium remaining in 

 a solution in which plants had been grown. Various ratios of these 

 three ions were employed, the total concentration beinu - SO parts pel- 

 million. They found widely varying amounts of these three ions 

 removed from the solution, and further there seemed to be a possible 

 difference of 20 to 30 per cent in the removal of any one without 

 an apparent effect upon the growth of the plants. Under the condi- 

 tions reported by them increased growth was correlated with increased 

 absorption. 



By means of conductivity measurements of solutions in winch pea 



seedlings were growing. True and Bartlett 14 - 15 ' 16 have determi I 



the rate of absorption and of excretion of electrolytes. Their work 

 was done with one, two and three salt solutions. In general they 

 found a greater absorption when a mixture of salts was present than 

 when single salts were used. Further, the absorption relationships 

 of salts with a common kation seem to be similar. For example, from 

 solutions of low concentrations, potassium chloride, potassium sul- 

 phate, and potassium nitrate are not removed, but on the other hand 

 there is an excretion of electrolytes by the plant. In direct contrast. 

 calcium nitrate and calcium sulphate are removed from their solu- 

 tions in every concentration employed and no excretion of electro- 

 lytes from the plants could be detected. It seems probable that the 

 low concentration employed by them acted as a limiting factor in 

 some cases. 



In a recent paper Breazeale 17 has shown thai the preset >f 



sodium carbonate, and sodium sulphate, when used in concent rat ions 

 of 1000 parts per million in nutrient solutions, decreased the absorp- 



isBot. Gaz., vol. 50 (1910), p. 1. 



w Amer. Jour. Bot., vol. 2 (1915), p. 255. 



is Ibid., p. 311. 



i« Ibid., vol. 3 (1915), p. 47. 



!" Jour. Agr. Besearch, vol. 7 (1916), p. 407. 



