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



DIFFUSION, PERMEABILITY 



469. Anonymous. [Rev. of: Findlay, Alexander. Osmotic pressure. 2nd ed., xi 

 + 116 p., 10 fig. Longmans Green & Co.: London.] Sci. Prog. [London] 14: 158-159. 1919. 



470. BuscALiONi, LtJiGi. Nuove osservazioni suUe cellule artificial!. [New observations 

 on artificial cells (conclusion).] Malpighia 28: 489-544. PL 3, fig. 1-2. 1920.— Experiments 

 of the author have confirmed previous discoveries and added new data in regard to artificial 

 cells, in which certain of the structures and physiological processes of living cells have been 

 reproduced. Appended to the article is an extensive bibliography (pages 521-540) annotated 

 by the author. — Edith K. Cash. 



471. Dixon, H. H., and T. G. Mason. A cryoscopic method for the estimation of sucrose. 

 Notes Bot. School Trinity Coll. Dublin 3: 83-89. 1920. — Since the depression of the freezing 

 point caused by a given quantity of sucrose in a given volume of water is approximately 

 doubled after inversion, the sucrose content of a solution can be determined by 2 cryoscopic 

 observations, — one before and the other after inversion. No preliminary treatment for the 

 removal of gums, etc., is necessary. Such treatment would be necessary for both polarimetric 

 and copper methods. By using the thermo-electric method of cryoscopy a very small 

 amount of plant sap (2| cc.) is sufficient for a determination. The probable error with this 

 method is a little greater than with Fehling's solution. — G. B. Rigg. 



472. Mason, T. G. On some factors affecting the concentration of electrolytes in the leaf- 

 sap of Syringa vulgaiis. Notes Bot. School Trinity Coll. Dublin 3: 67-82. 1920.— The 

 determination of the concentration of electrolytes in leaf-sap by conductivity observations 

 was found unsatisfactory unless allowance was made for the viscosity of the sap. To make 

 this correction, the conductivity of the sap was determined, then yrr KCl was dissolved in it 

 and the conductivity again determined. Then the conductivity of t^ KCl in aqueous solution 

 was determined. By comparing the value obtained by the last observation with the difference 

 between those obtained by the first 2 the effects due to viscosity were determined. — The 

 osmotic pressure of the cell sap is frequently mainly due to electrolytes, but the presence 

 of solutes that are neither electrolytes nor sugars may play a part. A tendency was found 

 for the content of electrolytes to vary inversely with that of the non-electrolytes. It is sug- 

 gested that these fluctuations are associated with the rate of carbon assimilation, which de- 

 termines the rate at which electrolytes are removed from solution in metabolism. — G. B. Rigg. 



WATER RELATIONS 



473. BoxJYOucos, George J., and M. M. McCool. Measurement of the amount of water 

 that seeds cause to become unfree and their water soluble material. Jour. Agric. Res. 20: 

 587-593. 1921. — The amount of unfree water, consisting of (a) capillary and adsorbed, and 

 (b) combined (water of hydration and water of solid solution), was determined by the type 

 of dilatometer used in a previous study of soils (see Bot. Absts. 9, Entry 535). Fourteen 

 different kinds of seeds were used. The amount of water that seeds cause to become unfree 

 is very large. Repeated freezing and thawing tend to diminish considerably the amount of 

 unfree water, especially in some seeds. Dry seeds contain a large amount of water-soluble 

 matter as is evidenced by the high freezing point depression. — Evelyn I. Fernald. 



474. Hill, T. G. The water economy of maritime plants. Sci. Prog. [London] 14:60-80. 

 1919. — The author carried out a series of experiments with halophytic plants, particularly 

 with such forms as Salicornia and Suaeda, on the coast of Brittany, supplemented by work 

 in the laboratory. The investigations were concerned primarily with (1) osmotic relations, 

 (2) transpiration, and (3) absorption. — It was found that the osmotic power of the cell sap of 

 the root hairs can be adjusted to the salt content of the soil. Transpiration was found to 

 be remarkably high and variable for the plants in question, and in all cases it was greater 



