232 LECTURES ON IMMUNITY 



(cf. p. 225). And it is even probable that the haemolysin 

 enters into combination with the molecules of the proto- 

 plasm inside the erythrocytes, just as tetanolysin or alka- 

 lies do (cf. pp. 103 and no); but concerning this reaction 

 we learned very little or nothing from my experiments. 



My measurements were founded upon determinations 

 of the degree of haemolysis exerted by a given mixture of 

 immune-body and alexin acting upon a given quantity 

 of erythrocytes. To this end i c.c. of a 5 per cent sus- 

 pension of erythrocytes (from sheep or ox) in physio- 

 logical solution of NaCl was mixed with 1.5 c.c. of a fluid 

 containing the desired quantities of immune-body and 

 alexin and additional physiological salt-solution until the 

 total volume was always 2.5 c.c. All the preparations were 

 kindly supplied by the Institute. 



After the blood suspension and the haemolytic mixture 

 had been each mixed thoroughly by shaking (for reasons 

 referred to above, cf. p. 15), the cell suspension was 

 poured into the mixture in a rapid manner, the test-tubes 

 containing the mixture were placed in an incubator at 37 C. 

 for 2 hours, after which time the test-tubes were taken out 

 and set into a refrigerator at about 2 C., where they 

 remained until the next morning (about 17 hours), when 

 they were examined and the degree of haemolysis deter- 

 mined by comparison with test-tubes containing different 

 quantities of the same variety of erythrocytes, laked in 

 distilled water. 



The immune-body and the alexin were left together for 

 about half an hour at room temperature (20-24 C.) before 

 the addition of the cell suspension, but the time of reaction 

 between these two substances seemed not to have a per- 



