The Hemolytic Amboceptor -325 



tubes i c.c. of the 5 per cent, suspension of sheep corpuscles 

 and i c.c. of the i : 10 dilution of the normal guinea-pig 

 serum (complement) are measured with graduated pipets, and 

 then to each of these tubes the rabbit serum (amboceptor) 

 is added in diminishing quantities for the purpose of de- 

 termining the least quantity that will bring about complete 

 hemolysis in two hours at the temperature of 37 C. The 

 occurrence of the hemolysis is shown by a very striking 

 change in the appearance of the fluids. The mixture is at 

 first opaque and pale red, but after hemolysis, or solution 

 of the red corpuscles, becomes a beautiful transparent 

 Burgundy wine red. 



The actual " set-up " or working scheme for determining 

 the unit or least hemolyzing addition of the amboceptor 

 serum may be represented as follows, the tubes being placed 

 in a thermostat and observed every fifteen minutes: 



Five per cent, suspen- Normal guinea-pig Hemolytic rabbit Result (final readings after 

 sion of corpuscles (c.c.). serum (c.c.). serum (c.c.). two hours). 



o.oi Complete hemolysis. 



0.005 



0.002 



O.OOI 



0.0005 



0.0003 Partial hemolysis. 

 0.0002 No hemolysis. 



o.oooi " 



After the reagents are added, enough 0.85 per cent, salt 

 solution is added to each tube to bring the total bulk of the 

 mixture up to 5 c.c. 



From the results shown in the tubes it is evident that the 

 hemolyzing quantity of the rabbit serum lies between 

 0.0005 an d 0.0003 c.c., and is probably 0.0004 c - c - To be 

 as accurate as possible, a second series of experiments should 

 be made with 0.0005, 0.00045, and 0.0004 c - c -> so that the 

 proportion of amboceptor serum necessary to effect hemolysis 

 be known within small limits. This least quantity, that will 

 certainly cause hemolysis in two hours at 37 C., is known 

 as the unit. The combination of the unit of corpuscular 

 suspension (i c.c.), the unit of complement (o.i c.c.), and the 

 unit of hemolytic amboceptor is known as the hemolytic 

 system. 



As soon as this unit is known accurately, we are in posi- 

 tion to reverse the conditions of the test. Thus, if we 

 should desire to know how much variation there may be in 

 the complements from different animals under different 



