No. 2, November, 1920] PHYSIOLOGY 117 



and demand a control analysis by analysts approved by the Quinine Bureau. As there are 

 several methods of analysis for quinine- content in vogue— the gravimetric, polarimetric, 

 etc., which vary somewhat in results — the Quinine Bureau is to appoinl a ( 'ommission to 

 study these in order to establish a uniform method with the ultimate object of creating a sin- 

 gle, central analytical laboratory. — E. N. Gathercoal. 



PHYSIOLOGY 



B. M. Duggar, Editor 

 Carroll W. Dodge, Assistant Editor 



DIFFUSION, PERMEABILITY 



828. Loeb, J. Influence of a slight modification of the collodion membrane on the sign of 

 the electrification of water. Jour. Gen. Physiol. 2: 255-271. 1920. — Continuing work pre- 

 viously reported, the author shows that in solutions of electrolytes which have a tendency to 

 induce negative electrification of water, that is, in solutions of acids, acid salts, and salts 

 with trivalent and tetravalent cations, the diffusion of the water depends, not only upon the 

 concentration and nature of the salts, but also upon the previous treatment of the membrane. 

 The treatment consisted in filling the collodion bags with 1 per cent gelatin solution and allow- 

 ing them to stand over night. This was followed by very thorough washing in water. The 

 differences in the osmotic behavior of the normal and treated collodion membranes seemed to 

 be due, not to alterations in permeability of the membrane, but to the fact that water, in 

 bags treated with gelatin, under the conditions named, diffuses as if positively charged. For 

 instance, when solutions of acid are separated from pure water by a gelatin-treated collodion 

 membrane, negative osmosis occurs, while, if a membrane, not so treated, is used, positive 

 osmosis occurs. A treatment of the collodion membrane with casein, egg albumin, blood 

 albumin, or edestin affects the behavior of the membrane as does treatment with gelatin. 

 Treatments with peptone, alanine, or starch have no such effects. — Otis F. Curtis. 



829. Loeb, J. Influence of the concentration of electrolytes on some physical properties 

 of colloids and of crystalloids. Jour. Gen. Physiol. 2: 273-296. 1920.— The effects of adding 

 an alkali or a neutral salt to a 1 per cent solution of metal gelatinate at P H = 8.4 or to neutral 

 solutions of salts with monovalent cations, such as Na 2 S0 4 or K 4 Fe(CN) 6 , etc., at concentra- 

 tions of M /256, are similar in that the initial rate of diffusion of water through untreated col- 

 lodion membranes towards these solutions is decreased and the permanent osmotic pressure 

 is also lessened. The effects of the addition of electrolytes on diffusion of water into neutral 

 solutions of salts with monovalent or bivalent cations can be explained on the basis that the 

 ions influence the electrification of water and the rate of diffusion of electrified water. The 

 similarity in the effects of electrolytes on initial diffusion of water through a membrane 

 towards either colloidal metal gelatinates or a crystalloidal salt, as well as the similarity in the 

 effects on osmotic pressure, suggests that the explanation of the phenomena is the same. If 

 this is the case, it raises the question whether the effects of ions on osmotic pressure of col- 

 loidal solutions, as well as on other physical properties of colloids, such as swelling, may be 

 due, not to their colloidal properties, but to the more general effects of ions on the electrifi- 

 cation of water and the diffusion of such electrified water through membranes. Not only was 

 there a similarity in the effects of ions on the diffusion of positively charged water particles 

 towards metal gelatinates and crystalloidal salts, but there was also a close similarity in the 

 effects of acids and neutral salts on the diffusion of negatively electrified water towards gela- 

 tin-acid salts and crystalloidal salts. — Otis F. Curtis. 



830. McCool, M. M., and C. F. Millar. Further studies on the freezing point lowering 

 of soils and plants. Soil Sci. 9: 217-233. 3 pi. 1920.— The amount of water which froze at 

 — 1.5°C. in the leaves of crop plants was found by the use of the dilatometer to vary with the 



