108 PROPERTIES OF H^EMOLYTIC SERA 



Two series (A and B) of seven tubes, each containing 

 5 c.c. of salt solution, are taken : 



1. To each tube in A 4 doses of IB and 0-2 c.c. anti-IB 

 (from guinea-pig). 



To each tube in B 4 doses of IB and 0-2 c.c. guinea- 

 pig's serum 55 (as a control). 



They are placed in the incubator for an hour at 37 C. 



2. 0-5 c.c. of suspension of red corpuscles is added to each, 

 and the tubes are again incubated for an hour. 



The contents of each tube are then washed and centri- 

 fugalized. The corpuscles in all the tubes have thus been 

 treated with the same amount of IB, those in series A being 

 treated with anti-IB also. We have thus to test how much 

 IB will be taken up in the two series. 



3. To the several tubes in the two series 1, 2, 3, 4, 5, &c., 

 doses of IB are added. 



4. After an hour the tubes are centrifugalized and the 

 separated fluid from each is added to red corpuscles along 

 with a sufficient amount of complement, in order to show 

 the amount of free IB in each. 



The result is that lysis is the same in both series, being 

 first complete in the fifth tube in each. As originally four 

 doses of IB were added and then five to this tube, this means 

 that whether anti-IB is present or not the same amount of 

 IB is taken up when nine doses of IB are added, one dose 

 remains free. 



We therefore conclude that the anti-immune-body in 

 question has no effect in interfering with the combination of 

 immune-body with the receptors of the red corpuscles. If the 

 anti-immune-body had prevented the union of immune-body 

 with the receptors of the red corpuscles, then we should have 

 found that in the series treated with anti-immune-body more 

 immune-body would have to be added subsequently before 

 one dose remained free than was necessary in the series 

 treated with immune-body alone. 



