19161 AGRICULTURAL BOTANY. 433 



salt, the permeability relations of other salts, and a discussion of the facts ob- 

 served. 



In leaves of Rhcco discolor, plasmolysis was rapid, reaching its maximum In 

 about 15 minutes, and then showing a reversal. Preliminary experiments with 

 other objects are said to indicate that the influence of salts on the permeability 

 of plasma may prove to be more widely prevalent than it is now known to be. 

 No support was found for the view that decrease of permeability is referable to 

 injury of the protoplasm. These experiments are considered to throw light on 

 the nonreversal of plasmolysis as sometimes observed, also to show that the in- 

 flow of salts does not necessarily proceed as far as equilibrium of the internal 

 and the external solutions. They are said also not to support the lipoid theory 

 regarding the uptake of nutrient materials. 



A bibliography is appended. 



Absoi-ption of ions by plants, E. Pantaxelli (Jahrb. Wiss. Bot. [Prings- 

 heim], 56 (1915), Pfeffer-Festschr., pp. 689-733) .—The author reports investi- 

 gations bearing upon the questions of the dependence between uptake of cations 

 and that of anions, changes in chemical reaction of the medium external to 

 the plant following ionization, antagonistic influences of ions as affecting up- 

 take, influence of concentration, curves of uptake, and mechanics of salt ab- 

 sorption. 



It is stated that the uptake of a salt by living plasma is a phenomenon of 

 adsorption. Ions of salts are absorbed separately and not in salt molecules as 

 wholes, cation and anion being generally absorbed in different proportions. Ion 

 adsorption is independent of water adsorption. Its rapidity differs with the 

 nattire of the ions involved and with time, but not uniformly. Above a certain 

 concentration, all ions lead to an increase of specific permeability, thtis opening 

 up a new field to adsorption. Evidence has been obtained of the separateuess of 

 extrapermeability and intrapermeability in this connection. Slight narcosis 

 decreases uptake of most, but not all, ions. Apparently, undetermined physio- 

 logical factors are operative. Slight narcosis may oppose uptake of nutritive 

 ions and may favor that of injurious ones. 



A bibliography is appended. 



Concerning the comparative rapidity of absorption of anions and cations 

 by plants. E. Bobko and E. N. SinskaII (Iz Rezul't. Veget. Opytov Lab. Rabat 

 {Rec. Trav. Lab. Agroi.), 9 (1913), pp. 44^--i55). — Barley, lupine, and pumpkin 

 were grown in the presence of potassium, ammonium, magnesium, and calcimn 

 sulphates. In another test barley alone was grown with potassium, sodium, 

 ammonium, and calcium chlorids. 



With sulphates it was definitely found that the ions are absorbed independ- 

 ently, although no such pronounced deviation from the original ratio as reported 

 by Pantanelli was observed between the absorption of the cation and the anion. 

 The same experiment showed that there is a connection between the absorption 

 of certain ions and changes in alkalinity, but no explanation of this phenome- 

 non is advanced. With chlorids, absorption of anions by barley prevailed over 

 absorpti<in of cations in all cases except that of ammonium chlorid. 



On the question of the equivalent absorption of anions and cations by 

 plants. G. I. RiTMAx (Rittman) (/c RezuVt. Veget. Opytov Lab. Rabat (Rcc. 

 Trav. Lab. Agrou.), 9 (1915), pp. 505-518). — These experiments were carried 

 out with peas to determine the relative intensity of absorption of the anions 

 and cations of calcium salts. The plants were grown in the dark as well as 

 in the light and examined at various stages of development. 



It was found that in all cases, the anions and the cations of the chlorids 

 and the sulphates were absorbed at the same rate, but with a tendency to a 



