162 ANTI-BACTERIAL PROPERTIES OF SERUM 



I. ABSORPTION BY RED CORPUSCLES TREATED WITH 

 IMMUNE-BODY (SENSITIZED RED CORPUSCLES) 



The method here is to introduce red corpuscles combined 

 with multiple doses of immune-body into a normal serum, 

 and then to determine what properties have been removed 

 from the serum. This is most conveniently done by fixing 

 the haemoglobin of the red corpuscles by heat, at a tem- 

 perature which does not destroy the receptors does not, 

 that is, interfere with their powers of absorbing immune- 

 body and thereafter complement. The following are the 

 details : 



Twenty c.c. of a 5 per cent, suspension of ox's corpuscles, 

 washed free of serum, in 0-85 per cent. NaCl solution are 

 taken, and excess of immune-body from a rabbit treated 

 with injections of ox's corpuscles is added. (The corpuscles 

 in question can take up about ten haemolytic doses of 

 immune-body, so we add rather more than this amount.) 

 After an hour is allowed for combination of the immune- 

 body the corpuscles are centrifugalized and washed in salt 

 solution. They are then placed overnight in a serum steri- 

 lizer at 55 C. By such an exposure to this temperature 

 the mixture has been changed into a turbid brownish 

 suspension, the corpuscles being clumped in small granular 

 masses, but the power of absorbing complement is still 

 retained. The mixture is then centrifugalized and the 

 altered corpuscles are washed twice in salt solution. After 

 the last centrifugalization the fluid is removed as com- 

 pletely as possible, and the deposited corpuscles are used for 

 testing their absorbing properties. 



The deposit obtained in the above manner is added to 

 1-5 c.c. of guinea-pig's normal serum, and the mixture is 

 placed in the incubator at 37 C. for one and a half hours. 

 The mixture is then centrifugalized and the serum is pipetted 



