IMMUNITY AND ANAPHYLAXIS 211 



the antigen of B. typhosus, using highly potent anti- 

 typhoid serum obtained from an immunized rabbit. 



Deviation of the Complement. Neisser and Wechs- 

 berg, experimenting with mixtures of specific inactivated 

 immune sera, specific antigen (bacteria) and complement, 

 found that, beginning with the complement in excess, 

 more and more bacteria were destroyed as the amount 

 of immune -body was increased, up to a maximum. 

 Beyond this, increase of the amount of immune-body 

 lessened bacteriolysis, and finally in great excess, seemed 

 to stop it entirely. To this phenomenon they gave the 

 name of " deviation of the complement," in accordance with 

 their theory that free immune-body has a greater affinity 

 for antigen than immune-body joined to complement ; 

 and so in great excess of immune-body, the immune-body 

 appropriates all the bacterial receptors, to the exclusion 

 of the immune-body joined to complement ; hence the 

 cessation of bacteriolysis. This explanation cannot now 

 be accepted, and so the term " deviation of the comple- 

 ment " is unfortunate and should be dropped. It is 

 possible that the explanation of the phenomenon should 

 be sought on physical lines, the excessive dilution of the 

 mixture with serum containing immune-body reducing 

 the chances of bacteriolysis by the complement in the same 

 time-limit ; and it is possible the complement may be 

 inhibited by other constituents of the serum added. 



Heterolysins, Isolysins, Autolysins. A haemolysin 

 produced in the blood of one animal by the injection 

 of the red cells of another species, is called a " hetero- 

 lysin." When the haemolysin is produced by injection 

 of red cells of a member of its own species, it is called an 

 " isolysin." Both of these have been produced. The 

 production of a haemolysin in an animal by the injection 

 of its own red cells, has not been accomplished. If such 

 a haemolysin were produced, it would be called an " auto- 

 lysin." The injection of isolysins produces " anti- 

 isolysins," which like the heterolysins and isolysins are 

 specific. The search for autolysins is clinically significant, 

 as a possible theory for paroxysmal haemoglobinuria. 



