RECENT ADVANCES IN SCIENCE 229 



ions, but that the beneficial effect of calcium in lowering the 

 harmful effects of sodium must take place in the plant. 



A similar series of observations has been made by D. D. 

 Waynick (Univ. California Publications in Agric. Science, 3, 

 135-242, 191 8), with barley growing in Shive's three-salt water 

 culture medium to which other salts were added in various 

 amounts and proportions. At the end of the experiment the 

 shoots and roots were analysed and the various ions deter- 

 mined. A great number of results are recorded. In every 

 case where the amount of growth was markedly reduced, the 

 analysis of the plant showed that an excessive amount of calcium 

 or magnesium had entered the plant. The author adduces 

 this result as further proof of the close relation between 

 antagonism and cell permeability. Both the experimental 

 results and conclusions thus appear to be strongly opposed to 

 those of Reed cited above. 



The earlier work of Pantanelli (Bull. Orto Bot. R. Univ. 

 Napoli, 5, 1-54, 191 5) on the absorption of ions by plants has 

 now been extended by a further series of observations (Bull. 

 Orto Bot. R. Univ. Napoli, 6» 1—37, 191 8). Species from dif- 

 ferent parts of the plant kingdom were investigated — namely, 

 Lupinus albus, . Vicia faba, onion, Valonia utricularis, and 

 yeast, and the absorption of ions from a number of salts deter- 

 mined by chemical analysis of the culture solutions in which 

 the plants were growing. The author confirms his earlier 

 observation that the ions of a salt are absorbed independently 

 of one another, and this holds both for the early rate of absorp- 

 tion and for the total quantity absorbed. The phenomenon 

 is quite general, and holds equally for flowering plants and 

 Thallophyta. For instance, in the absorption of anion from 

 potassium chloride (0*02 N), after four days the quantity of 

 chlorion absorbed is almost twice the quantity of potassium 

 taken up, measured in equivalents (milligram-ions). Similarly, 

 in the case of Valonia, after sixteen hours the ratio of kation 

 to anion absorbed was found to be 16*7, an extreme case of 

 independent ionic absorption. The rate at which the ions are 

 absorbed varies with the species very greatly ; in general any 

 particular ion is absorbed much more rapidly by unicellular 

 organisms or by organs rich in protoplasm than by pericellular 

 organisms or by organs poor in protoplasm. Not merely are 

 the rates of absorption of different ions different, but this rate 



