ON ANTI-IMMUNE-BODIES 103 



corpuscles). To each of the tubes in one series (A) we add 

 0-3 c.c. of anti-immune-body; to the tubes in series B, 0-3 c.c. 

 of normal guinea-pig's serum heated at 55 C. as a control. 

 The tubes are placed in the incubator at 37 C. and after 

 an hour they are centrifugalized and the contents washed 

 with salt solution. They are again centrifugalized and the 

 salt solution is pipetted off. To each tube is added 0-5 c.c. of 

 guinea-pig's serum heated at 55 C. We have thus two 

 series of tubes, in one of which the corpuscles are combined 

 with IB and anti-IB, in the other only with IB. We then 

 test the effects of complement by adding varying amounts 

 to the several tubes. It is found that in series A 0-1 c.c. of 

 complement produces practically no lysis, whilst in series 

 B the same amount produces complete lysis. In series A 

 even 0-2 c.c. of complement produces only slight lysis. 



ON THE MODE OF ACTION OF ANTI-IMMUNE-BODY 



Does the anti-immune-body act by preventing the union 

 of complement with the red corpuscles treated with immune- 

 body or by in some way inhibiting the toxic action of comple- 

 ment ? The former will be shown to be the case, if we 

 separate the fluid from a tube in which lysis has been pre- 

 vented by anti-immune-body and find that it contains 

 uncombined complement, the test being made in the usual 

 way by adding red corpuscles treated with immune-body 

 and observing whether lysis results. Experiments carried 

 out on these lines show clearly that in every case where the 

 anti-immune-body prevents lysis, complement has been kept 

 out of combination. This is in confirmation of the result 

 arrived at by Bordet. In our initial experiments the red 

 corpuscles were suspended in guinea-pig's serum 55, in 

 accordance with Bordet's method, but we afterwards used salt 

 solution as the medium of suspension and investigated the 

 action of the anti-immune-body in general, even where lysis 



