No. 2, September, 1920] PHYSIOLOGY 281 



the rate of diffusion of water towards the solution is rapidly increased, which is apparently 

 due to increased attraction for the water by the ions hearing a charge opposite to that borne 

 by water. With a further increase in concentration from M/250 to about M/16. depending 

 somewhat upon the nature of the electrolyte, the rate of the diffusion of water towards the 

 solution is less than that at weaker concentrations, which is apparently due to a more rapid 

 increase in the repelling action of that ion bearing the same charge as the water particles. 

 In fact, this repelling action may become so dominant as to develop negative osmosis when 

 diffusion takes place from the solution toward the pure water decreasing the volume of the 

 solution. Therefore, within the range above stated, the reverse of what would be expected 

 from van't Hoff's law is observed; that is, with an increase in concentration of the electro- 

 lyte, the attraction for water diminishes. This was demonstrated with a number of solutions, 

 in some cases when water behaved as if positively charged and repelled by the cations, and 

 in others when it behaved as if negatively charged and repelled by anions, especially those 

 with higher valences. When experimenting to determine the effects of solutions on the 

 diffusion of negatively charged water, it was necessary to use membranes previously treated 

 with gelatin. — Otis F. Curtis. 



2143. MacDougal, D. T., and H. A. Spoehr. The solution and fixation accompanying 

 swelling and drying of biocolloids and plant tissues. Plant World 22 : 129-137. 1919. — Desic- 

 cated slices of Opnntia discata showed vigorous swelling in water, dilute acids, alkalies, and 

 salt solutions; but on being dried after the first swelling, they exhibited a greatly reduced 

 power of swelling. Substances giving the sections their high imbibition capacity are believed 

 to be extracted during the first swelling. The loss during the first swelling was about 7 per 

 cent of the total solids, and mainly amino-acids, hexoses, malates, and salts. Biocolloids 

 like agar and gelatine-agar show similar losses during swelling, about 15 per cent being 

 extracted. Reduced swelling after extraction and drying may also be related to changes 

 in the colloidal mesh, aggregations, or coagulations which cannot be reversed by simple 

 hydration. — Charles A. Shull. 



2144. Paterno, E. Origini e sviluppo della crioscopa. [Origin and development of cryos- 

 copy.] Gaz. Chim. Italiana 49: 381-411. 1919. — A historical study and digest of the litera- 

 ture on the subject of cryoscopic methods, and measurements, chiefly considered from the 

 standpoint of pure chemistry. — A. Bonazzi. 



WATER RELATIONS 



2145. Harding, S. T. Relation of the moisture equivalent of soils to the moisture proper- 

 ties under field conditions of irrigation. Soil Sci. 8:303-312. 6 fig. 1919.— See Bot. Absts. 5, 

 Entry 2320. 



2146. Hill, Leonard, and Hargood-Ash, D. On the cooling and evaporative powers of 

 the atmosphere, as determined by the Kata-thermometer. Proc. Roy. Soc. London 90B: 

 438-147. 1919. — Data are presented endorsing the efficiency and applicability of the Kata- 

 thermometer as an instrument for determining the cooling and evaporative powers of the 

 atmosphere. — R. W. Webb. 



2147. Middleton, Howard E. The moisture equivalent in relation to the mechanical 

 analysis of soils. Soil Sci. 9: 159-167. / fig. 1920.— See Bot. Absts. 5, Entry 2331. 



■>i 



!148. Satre, J. D. The relation of hairy leaf coverings to the resistance of leaves to trans- 

 piration. Ohio Jour. Sci. 20: 55-75. 7 fig. 1920. — Mullein (Verbascum lhapsus) leaves offer 

 greater resistance to water loss in darkness than in light and less in wind than in still air, 

 when compared to tobacco {Nicotiana sp.) leaves, and they respond as much or more to en- 

 vironmental changes. Removal of hairs does not alter resistance of mullein leaves in still 

 air and light; but slightly decreases resistance in wind and light, and greatly decreases re- 

 sistance in still air and darkness, because the cuticular surface is more exposed. In darkness 



