262 PHYSIOLOGY [BoT. Absts., Vol. IX, 



the Asiatic and will probably be in demand when normal supplies of Asiatic styrax are again 

 available. — C. M. Sterling. 



1614. White, F. Ashford. A glimpse of Grasse, the home of the French perfumery 

 industry. Amer. Druggist and Pharm. Rec. 68«: 18-20. 7 fig. 1920. 



PHYSIOLOGY 



B. M. DuGGAR, Editor 

 Carroll W. Dodge, Assistant Editor 



(See also in this issue Entries 1258, 1291, 1323, 1344, 1385, 1497, 1409, 1410, 1415, 1419, 



1481, 1490, 1492, 1495, 1539, 1611, 1664) 



DIFFUSION, PERMEABILITY, ADSORPTION 



1615. LoEB, Jacques. Ionic radius and ionic efficiency. Jour. Gen. Physiol. 2: 673- 

 687. 1920. — The writer has previously demonstrated that when solutions of electrolytes are 

 separated from water by membranes, the ions with the same sign as that of the membrane 

 increase while ions of opposite sign decrease diffusion of water through the membranes, and 

 that the effects of these ions increase with an increase in valency. Aside from valency the 

 so-called ionic radius, the distance between the central positive nucleus and the outermost 

 ring or shell of electrons, also influences the rate of water diffusion. It is shown in this paper 

 that the accelerating and depressing effects of anions increase directly with the order of magni- 

 tude of their radii in the order Cl <Br <I, while these effects of cations increase inversely as 

 the radii in the order Rb <K <Na <Li. This is explained on the assumption that the actionof 

 ions is electrostatic. The effect of the extra positive charge on the nucleus of a cation, there- 

 fore, will be greater the smaller the radius, while the effect of the excess electron of the anion 

 will be greater the greater its distance from its own positive nucleus. It is suggested that 

 a similar explanation might be adjusted to apply to polyatomic ions. — Otis F. Curtis. 



1616. LoEB, Jacques. The reversal of the sign of the charge of collodion membranes by 

 trivalent cations. Jour. Gen. Physiol. 2: 659-671. 1920. — The writer gives evidence to show 

 that a collodion membrane treated with protein becomes positively charged when in contact 

 with salts of trivalent cations. This reversal of charge is similar to that induced by acid 

 (see Bot. Absts. 8, Entry 607). The reversal of the charge induced by trivalent cations, 

 however, occurs on the alkaline side of the isoelectric point of the protein. Collodion mem- 

 branes not treated with protein can not be induced to assume a positive charge by treatment 

 with either trivalent cations or acid. — Otis. F. Curtis. 



WATER RELATIONS 



1617. HoTTES, C. F. A constant humidity case. [Abstract.] Phytopath. 11:51. 1921 



MINERAL NUTRIENTS 



1618. Anonymous. Disintegration of roofing tile. Sci. Amer. Monthly 3 : 244. 1921. — 

 The contributor quotes J. Scott (British Clay Worker 29: 138-140. 1920) to the effect that 

 Mucor racemosa attacks roofing tile and thus obtains part of its food, causing the tile to 

 disintegrate. — Chas. H. Otis. 



1619. Dickson, James Geere. The relation of certain nutritive elements to the composi- 

 tion of the oat plant. Amer. Jour. Bot. 8: 256-274. 2 fig. 1921. — The effect of limiting cer- 

 tain essential nutrient elements upon the chemical composition of the plant was studied. Pedi- 

 greed Swedish oats. Arena sativa aristata, were grown in sand cultures watered by nutrient 

 solutions. The latter consisted of a modified Knop's solution (as a control) and 5 other modi- 

 fied solutions, in each of which 1 of the elements magnesium, calcium, potassium, phosphorus, 



