GENERAL PROPERTIES: THE CORPUSCLES. 423 



pressure as plasma as determined by the effect of each on the 

 lowering of the freezing-point (see Appendix, Diffusion, Osmosis, 

 and Osmotic Pressure). Such a solution mixed with blood 

 should not and does not alter the water contents of the corpuscles. 

 One may, in fact, use a 0.7 per cent, solution of sodium chlorid 

 without causing any noticeable hemolysis, and this strength of 

 solution is frequently employed in infusions and experimental 

 work; it constitutes what is known in the laboratories as nor- 

 mal saline or physiological saline. If, however, one uses a 

 lower concentration, some of the corpuscles are hemolyzed, 

 and the number of corpuscles destroyed and the rapidity of 

 the hemolysis increase rapidly with the lowering of the osmotic 

 pressure.* While a 0.9 per cent, solution of sodium chlorid 

 suffices in most cases for infusions and for diluting blood, 

 it does not entirely replace the normal plasma or serum, since 

 these liquids, in addition to the sodium salts, contain salts of 

 calcium, potassium, magnesium, etc., each of which has doubtless 

 a certain specific importance. In diluting blood outside the body, 

 when the dilution is large, better results are obtained by using what 

 is known as Ringer's mixture, which consists of the physiological 

 saline solution plus small amounts of potassium and calcium 

 chlorid. One formula for Ringer's solution is: 



Sodium chlorid 0.9 per cent. 



Calcium chlorid 0.026 " " 



Potassium chlorid 0.03 " " 



Hemolysis Caused by the Action of Hemolysins. It has long been 

 known that the serum of one animal may destroy the red corpuscles 

 of another animal. Thus, rabbits' blood corpuscles added to the 

 clear serum of a dog, cat, or man are quickly destroyed, with the 

 liberation of their hemoglobin. This action was formerly described 

 under the term " globulicidal action of serum," and was compared 

 to the similar destructive (bactericidal) action, exhibited by serum 

 toward some bacteria. In more recent literature the term hemol- 

 ysis has replaced that of "globulicidal action/' and the hemolytic 

 effect that a serum may exert upon foreign corpuscles is attributed 

 to the presence in it of certain substances which in general are classed 

 as hemolysins. This hemolytic action is not due to a simple differ- 

 ence in osmotic pressure. The serums of the different mammalia 

 have all approximately the same osmotic pressure; the differences 

 are too slight to explain the effects observed. Moreover, if the 



* According to Brachmachari ("Studies in Hemolysis," Calcutta, 1913) 

 the red corpuscles in human blood begin to hemolyze in ~ solutions of sodium 

 chlorid, and the hemolysis increases rapidly between this concentration and ^ 

 solutions. Some corpuscles, however, retain hemoglobin even when the blood 

 is diluted with nine times its volume of distilled water. 



