﻿344 MARSHALL. 



a fermentative or enzyme-like nature. The instability of complement 

 is a more or less permanent characteristic, and equally characteristic are 

 the facts that complement is normally present in varying amount in 

 fresh serum, and that the quantity can not be influenced by the usual 

 processes of immunization, provided the health of the animal remains 

 unimpaired. If either of the first two characteristics fails, we have at 

 present no means at our disposal of recognizing complement. A number 

 of convincing arguments have been brought forward to prove that there 

 are different complements in different serums, and also that any one 

 specimen of serum contains a number of complements, although other 

 observers claim that all forms of complement action are due to a single 

 substance or form of energy in the serum. Whether complement has 

 other actions we do not know, nor whether it is capable of uniting with a 

 variety of other substances. Similarly, we do not know anything of anti- 

 complement except the one fact that it prevents the action of complement. 

 Whether a variety of substances or conditions could be the cause of such 

 an inhibition was not determined at the time that anti-complements were 

 first considered. Bordet(l) claims that specific anti-complements can be 

 produced, the action of which is different from that occurring in comple- 

 ment deflection, and Marshall and Morgenroth(20) found it possible with 

 a nonspecific anti-complement -to block out certain definite complement 

 activities from a serum without interfering with its other complement 

 actions. On the other hand Pfeiffer and his colleagues (10:30) claim 

 that the phenomenon of complement deflection explains reactions hitherto 

 accounted for as the result of anti-amboceptor acti'on. 



The phenomenon of complement deflection was first described in 1901 

 by Bordet and Gengou(5) who found that haemolysis was no longer pro- 

 duced in properly prepared corpuscles if the complement-containing 

 fresh serum was previously added to a mixture of bacterial emulsion and 

 specific anti-bacterial serum. 



In 1905, Gay (11, 12, 13), in Bordet's laboratory, discussed this phe- 

 nomenon, and concluded that the complement was removed by the 

 union of specific precipitin with precipitable substance. He found, as 

 Sachs (32) did also, that the immune body was not affected in this 

 reaction, only the complement being removed. He attributed the well- 

 known Neisser-Wechsberg phenomenon of deflection and the antilytic 

 action of normal serum described by Pfeiffer and Friedberger, and the 

 anti-complementary action of normal serum described by Sachs, to the 

 same phenomenon of precipitation. He holds that the above-mentioned 

 investigators overlooked minute traces of precipitable substance which 

 remained attached to the corpuscles, etc., after one washing with salt 

 solution, and which could be removed only by repeated washings. 



Moreschi(22, 23), working independently of Gengou and Gay, ob- 

 tained similar results. His experiments led him to conclude that our 



