104 PROPERTIES OF ILEMOLYTIC SERA 



is not prevented. The details of method are of similar 

 nature in the two cases and are given below. 



Bordet found that the action of anti-immune-body could 

 be demonstrated when the corpuscles were suspended in 

 guinea-pig's serum 55 C., whereas this result was usually 

 not obtained when they were suspended in salt solution. 

 A priori it is unlikely that the action of anti-immune-body 

 is not identical in the two conditions, and we have investi- 

 gated whether this is the case. We find that in salt solution 

 the effect of anti-IB can be demonstrated in two ways : 

 (a) by its delaying lysis, and (b) by its keeping out comple- 

 ment. We proceed as before by adding immune-body and 

 anti-immune-body to the one series of tubes containing 0-5 c.c. 

 suspension of red corpuscles, and to the other series immune- 

 body and normal guinea-pig's serum heated at 55 C. After 

 the corpuscles have been washed, complement is added in 

 varying amounts. 



A. Red corpuscles + 5 doses of IB + 0-25 c.c. anti-IB. 

 Amounts of guinea-pig's C 0-01, 0-015, 0-02, 0-025, 



0-03, 0-04, 0-05, 0-06 c.c. 

 Dose of C = 0-005 c.c. 

 Amount of C taken up in 1 J hours at 37 C. =0-012 c.c. 



B. Red corpuscles + 5 doses of IB + 0-25 c.c. guinea- 



pig's serum 55 C. 

 Amounts of C added as in A. 

 Amount of C taken up = 0-023 c.c. 



The difference in the amount of complement taken up in 

 the two series is thus very striking, being 0-011 c.c. or more 

 than two hsemolytic doses of C, this amount being kept out 

 by the action of anti-IB. 



The action of the anti-IB was also shown by the compara- 

 tive rapidity of the initial lysis in the two series. After 

 twenty-five minutes, lysis in series A was just complete in the 

 tube containing 0-04 c.c. of complement, whilst at the same 



