16 PROPERTIES OF ILEMOLYTIC SERA 



said to be three possibilities : (1) the surplus molecules of 

 immune-body may be destroyed in the process of haemolysis ; 

 (2) they may become free in the fluid ; or (3) they may 

 remain in union with the receptors of the red corpuscles. It 

 is easy to show in the first place that they are not destroyed, 

 as abundant immune-body can be obtained from the red 

 fluid resulting from the haemolytic action. 



Example : 1. Red corpuscles (say one cubic centimetre suspen- 

 sion) are treated with excess of immune-body, and after suitable 

 time is allowed for combination they are centrifugalized and washed 

 several times in salt solution. 2. Sufficient complement is added to 

 produce complete haemolysis. 3. One cubic centimetre of untreated 

 corpuscles is then added to the red fluid and the mixture is placed 

 in the incubator for an hour at 37 C. (No haemolysis occurs because 

 there is no free complement.) 4. The added corpuscles are then 

 separated by centrifugalization and washed in salt solution. On the 

 addition of complement they undergo complete haemolysis. 



As mentioned above, free immune-body unites with red 

 corpuscles at C. We may accordingly test whether 

 immune-body is recoverable from the red fluid at this tem- 

 perature. The steps are the same as in the above experiment, 

 only after haemolysis has occurred at Stage 2 the tube is 

 placed in a mixture of ice and water, the fresh corpuscles 

 are then added, and the mixture is allowed to remain at 

 C. for an hour. Afterwards the tube is centrifugalized 

 and the corpuscles are washed in cold salt solution. Com- 

 plement is then added to the corpuscles and the tube is 

 placed in the incubator. The result is that there is practi- 

 cally no lysis, though a control with red corpuscles added 

 to fluid containing a dose of immune-body at C. and then 

 centrifugalized, gives complete haemolysis on the addition 

 of complement. 



We may therefore conclude that when red corpuscles 

 containing several doses of immune-body are haemolysed by 

 the minimum dose of complement, the surplus molecules of 



