THE COMPOUND H^EMOLYSINS 233 



ceptible influence, as special experiments indicated. As 

 has been said, probably the chemical reaction takes place, 

 at least chiefly, in the interior of the red blood-corpuscles, 

 and under such circumstances it is easy to understand 

 that the time of reaction between immune-body and alexin 

 prior to the addition of the blood is of little or no conse- 

 quence. Since we know the haemolysed quantity, we wish 

 to calculate from it the quantity of haemolysin. For this 

 purpose we may employ the rule that the hasmolysed quan- 

 tity is nearly proportional to the square of the quantity of 

 acting haemolysin. If this rule for low concentrations 

 of haemolysin does not lead to quite exact results, this 

 result does little harm, for the chief thing is to find 

 instances in which the quantity of haemolysin is the 

 same, and this occurs, evidently, as soon as the degree 

 of haemolysis is the same. Approximately the quantity 

 of haemolysin is proportional to the square root of the 

 known quantity of haemolysis. In reality we make use 

 of this rule only in order to set forth the observations in 

 a simple manner. 



As illustration I reproduce here a series of experiments 

 with red blood-corpuscles from the ox. The immune-body 

 was prepared by injection of such erythrocytes into the 

 veins of a goat. The alexin was normal serum of guinea- 

 pigs. The arbitrary units employed are o.ooi of a c.c. 

 of the preparations containing immune-body or serum of 

 guinea-pigs. The unit of haemolysin is a hundredth part 

 of the quantity necessary for total haemolysis of the fixed 

 quantity of blood-corpuscles. The first of the following 

 series gives the observed haemolysed quantities, the second 

 the quantities of haemolysin (square root of the foregoing 



