158 PROPERTIES OF ANTI-SERUM TO SERUM 



complement action are capable of another explanation. 

 The question must be left an open one and requires fresh 

 investigation in the light of the facts established with 

 regard to deviation (vide also p. 39). 



SUMMARY OF RESULTS 



1. A mixture of serum and its anti-serum has the property 

 of fixing or deviating complement and thus interfering 

 with haemolysis. In this there is a close analogy to the 

 fixation of complements by cell-receptors in association with 

 immune-bodies. 



2. A large number of different complements may be fixed 

 by the same combination of serum and anti-serum : some 

 complements, however, may not be fixed. 



3. The amount of homologous serum necessary to produce 

 a distinct deviation of complement is extremely small 

 0-000,01 c.c. and even less : as a rule it is many times less 

 than the amount necessary to give a visible precipitate with 

 the anti-serum. 



4. When a precipitate forms, the deviating substance is 

 present in the precipitate and may be so exclusively : pre- 

 cipitation is, however, not essential, as the deviation pheno- 

 menon may be given by an anti-serum without the formation 

 of a precipitate. 



5. The precipitin and deviation tests give results which 

 are in great part in accord as regards specificity. 



6. For any given amount of anti-serum there is an 

 optimum amount of homologous serum which gives maxi- 

 mum deviation of complement : above, as well as below, 

 the optimum the deviation diminishes. 



7. The deviation phenomenon produces an effect similar 

 to an ' anti-complement ' action and the views generally 

 held with regard to anti-complements require revision. It 

 is, however, still left an open question whether true anti- 

 complements exist. 



