96 THE BLOOD AND THE LYMPH 



purposeful division in order to increase the total surface of the red 

 cells. The ultimate fate of the red cell fragments is not known. It is 

 reasonable to suppose that the fragmented bits containing hemoglobin 

 are carried to the liver, where the hemoglobin is transformed into 

 hematin and bile pigments. 



Hemolysis 



Another method of red blood cell destruction, which, however, does 

 not take place normally, is by hemolysis. The nature of the combina- 

 tion of the hemoglobin with the stroma of the red cell, as already re- 

 marked, is not definitely known. That it is not merely contained in a 

 sac is shown by the fact that the cell may be cut into bits without the 

 hemoglobin being set free. In some manner the hemoglobin is chem- 

 ically bound with the stroma of the red cell, from which it can be 

 freed by a number of physicochemical and chemical agents. This proc- 

 ess is known as hemolysis, and the substances which bring it about are 

 known as hemolytic agents. The manner in which these agents effect 

 the release of hemoglobin from the blood is quite varied. 



If the osmotic pressure of the plasma is lowered by dilution, the pres- 

 sure within the corpuscle remains high, and water is absorbed by the 

 cell. If this absorption is sufficient, the cell ruptures and the hemoglobin 

 is discharged. For this reason it is necessary in diluting the blood to 

 use solutions of salt having an osmotic pressure equal to that of the 

 blood to protect the red cell from hemolysis. This is obtained by using 

 a 0.9 per cent solution of sodium chloride. Better results are had, 

 however, by using either Ringer's solution (0.9 per cent NaCl, 0.026 

 per cent CaCl 2 , and 0.03 per cent KC1) or Locke's solution (0.9 per cent 

 NaCl, 0.024 per cent CaCl 2 , 0.042 per cent KC1, 0.01-0.03 per cent 

 NaHC0 2 and 0.1 per cent, glucose). 



In normal corpuscles hemolysis occurs to a small extent in solu- 

 tions containing about 0.42 per cent of sodium chloride. In certain 

 diseases the fragility of the corpuscles may be increased (Butler 7 ). 



The membrane and stroma of the erythrocyte contain lipoidal ma- 

 terial which is soluble in alcohol, ether, fatty acids, and bile salts. 

 Addition of these agents to the blood brings about hemolysis, presum- 

 ably by dissolving the lipoidal material present. The hemolysis which 

 occurs with saponin is similar in type, since saponins combine with 

 lipoids, the compound being soluble in water. 



The hemolytic properties of serum, whether they are found to be 

 normally present when the bloods of certain animals are mixed or to 

 be produced artificially by the injection of foreign red cells, furnish a 

 subject of great interest from the standpoint both of immunology and 



