Ralph W. Webster 



II. EXPERIMENTS ON RED BLOOD -CORPUSCLES 



It seems to be generally agreed that these cells may be regarded as systems sur- 

 rounded by semi-permeable membranes. If two solutions of different osmotic pressur-^ 

 be separated by a more or less elastic, semi-permeable membrane, an attempt is made to 

 equalize the pressure on each side of this membrane, with the result that phenomena 

 occur of swelling or of shrinking of the cell in question. 



Bonders, Hamburger, Koeppe, Gryns, Hedin, Overton, Roth, and others have con- 

 cluded, from their work on these corpuscles, that the phenomena mentioned above 

 depend on the difference of osmotic pressure between the solution outside and that 

 inside the corpuscular membrane, which membrane may be regarded as a thickening of 

 the protoplasm of the corpuscle. So convinced is Koeppe of the r6le of osmotic pres- 

 sure in life phenomena that he gives expression to the generality : "We cannot imagine 

 a single phenomenon in the living organism in which osmotic pressure may not have 

 a share." 



One of the most important points to be considered in this discussion of effects of 

 difference in osmotic pressure is that of the permeability of the corpuscle to the mole- 

 cules, or ions, of the substances investigated. If it can be shown that the corpuscle be 

 permeable to these particles, then, of course, the laws of diffusion replace those of 

 osmotic pressure. The process, in this latter case, would then resolve itself simply into 

 a discussion of the relative rate of diffusion of the various particles in question. 



Certain facts and experiments show, rather conclusively, that the corpuscular mem- 

 brane is to be regarded as a semi-permeable membrane, permeable to the molecules of 

 water (and to ions, or molecules, of certain inorganic and organic substances) but imper- 

 meable, to a large extent, to substances in solution both as regards the solution inside 

 and that outside the membrane. As Koeppe states, the red corpuscles contain no 



sodium chloride, while the serum contains 5.546 gms. in 1,000 gms. On the other hand, 

 the corpuscles contain 3.679 gms. of potassium chloride, while the serum contains 

 only .39 gms. in 1,000 gms. These facts, in themselves, show that the corpuscle is 

 impermeable to the ions of the salts in question, else an equilibrium would be estab- 

 lished on both sides of a permeable membrane. Gryns, Eykman, Hedin, and Oker- 

 Blom have carried out extensive series of experiments to show the relative permeabil- 

 ity of the corpuscle to various substances. Gryns, in his work on Influence of Dis- 

 solved Substances upon Bed Blood-Corpuscles in Connection with Bhenomena of Osmo- 

 sis and Diffusion, gives a tabular list of substances to which the corpuscle is permeable 

 and impermeable. Among these we find salts of metals, certain NH^ salts, such as 

 sulphate, nitrate, phosphate, and tartrate, glycocoll, sugar, etc., to be incapable of pen- 

 etrating the corpuscle ; while other NH^ salts, such as chloride, bromide, and oxalate, 

 alcohol, glycerine, urea, etc., easily penetrate this cell. Hedin and Oker-Blom, work- 

 ing with methods different from those of Gryns, confirm his results. 



A fact of the utmost importance in this discussion of the permeability of the cor- 

 puscular membrane, as well as of any other membrane, to different substances is the 

 following : A removal of free ions from a solution is possible only when ions of oppo- 



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