374 INFECTION AND IMMUNITY. 



the conditions would be ideal if immune human 

 serum were available for therapeutic purposes. 



If one depends on the complement in the pa- 

 tient's body for activation of the amboceptors, 

 there are two possible difficulties of importance: 

 First, the native complement of the body is often 

 decreased during infections and in some chronic 

 diseases and may be too little for thorough activa- 

 tion; second, the amboceptors of the immune 

 serum may demand for their activation a comple- 

 ment or complements which the body does not con- 

 tain. 

 Diversion of Diversion of complement has been referred to as 



Complement. , . . . . , , T 



a phenomenon seen in test-tube experiments, in 

 this condition an excess of amboceptors in some 

 way decreases the power of the serum; by an ex- 

 cess of amboceptors one means, in this instance, 

 such a quantity that many are unbound by the 

 bacteria. It is supposed that a certain amount of 

 the complement is absorbed by free or unbound 

 amboceptors, hence the effect is like that of too 

 little complement. In the desire to administer a 

 sufficient amount of antibodies, so much may be 

 introduced that diversion of the complement oc- 

 curs in the body. Eesults obtained by Loffler and 

 Able, by Pfeiffer and by Buxton and others, in 

 which excessive doses of immune serum were less 

 protective than moderate doses, show that a simi- 

 lar phenomenon occurs in the body. 



j n certain diseases the microbes are so situated 



that a serum as ordinarily administered may not 

 be able to reach them. Pfeiffer thinks that there 

 is little hope for the serum treatment of cholera 

 because of the exclusive location of the living or- 

 ganisms in the intestinal tract. In typhoid also 



