HEMOLYSIS OR ERYTHROCYTOLYSIS 189 



occurs. As hemoglobin is perfectly soluble in the salt solution, 

 it should pass out if it diffused as do the salts. Since there is 

 no escape of hemoglobin in such a salt solution, it is evident 

 either that the stroma is not permeable to hemoglobin, or else 

 the hemoglobin is in some way attached to or combined with 

 the stroma. Again, if the corpuscles are placed in a solution of 

 salt more concentrated than their own fluids, water escapes and the 

 corpuscles shrink ; as no hemoglobin escapes with the water, it 

 is evident that the stroma is not permeable to hemoglobin when 

 intact. Because of the resemblance of the process of hemolysis 

 to the rupture of plant cells with escape of their contents when 

 they are placed in distilled water, it might be assumed that 

 hemolysis is largely a physical matter, but there are many indi- 

 cations that chemical changes must be involved. For example, 

 if a red corpuscle in an isotonic solution is cut into pieces, the 

 hemoglobin does not escape, indicating that its structure is quite 

 dissimilar to that of the simple vegetable cell, and that there is 

 some union of stroma and of hemoglobin other than a physical 

 union. 1 



Repeated alternate freezing and thawing is another physical 

 means of bringing on hemolysis. Heating to 62 -6 4 C. causes 

 hemolysis of mammalian corpuscles ; in cold-blooded animals 

 this seems to occur at a slightly lower temperature. 



Some chemical agents are capable of liberating hemoglobin, 

 even when the corpuscles are in isotonic solutions. The ordi- 

 nary salts of serum, of course, do not have this property, but 

 ammonium salts are strongly hemolytic. The chemical agents 

 that dissolve red corpuscles seem to be those that have the power 

 of penetrating the stroma. Ammonium salts and urea penetrate 

 the corpuscles freely and causes hemolysis. Sugar and NaCl 

 seem not to* penetrate the corpuscles, and therefore do not pro- 

 duce hemolysis. Of the permeating substances, there seem to be 

 two types : one, like urea, does not produce hemolysis when 

 in a solution of NaCl isotonic with the serum ; the other, like 

 ammonium chloride, is not prevented from producing hemolysis 

 by the presence of JSaCl. 2 



1 Stewart (Jour, of Physiol., 1899 (24), 211) found that in hemolysis by 

 physical means or under the influence of serums, there is no marked increase 

 in the electrical conductivity, but hemolysis by saponin and by water causes 

 an increase of conductivity, presumably because of the escape of electrolytes. 



2 Hamburger, in his book, " Osmotischer Druck und lonenlehre," reviews 

 exhaustively the physical chemistry of hemolysis. The following is his sum- 

 mary of the permeability of red corpuscles by various substances : 



Organic Substances. (a) Impermeable for sugars; namely, cane-sugar, dex- 

 trose, lactose, also arabit and mannit. (b) Permeable for alcohols, in inverse 

 proportion to the number of hydroxyl groups that they contain ; also for aide- 



