382 HEMOLYSINS 



A series of small test-tubes (10 by 1 cm.) are marked appropriately 

 and placed in a rack. To each tube 3 c.c. of the various hypotonic salt 

 solutions and 0.05 c.c. of the red blood-corpuscles (about 1 drop) are 

 added. The salt solution and corpuscles in each tube are well mixed, 

 and the whole series is placed in the refrigerator for from eighteen to 

 twenty-four hours, after which the readings are made. 



The tube of lowest dilution even if it shows but a trace of hemoly- 

 sis represents the point of minimal resistance. The strength of salt 

 solution in which all the corpuscles are hemolyzed represents the maxi- 

 mal resistance. 



Normally, the minimal resistance is about 0.47, and the maximal 

 resistance about 0.3 (Morris). 



