B ACT ERIOLY SINS AND H JEM OLY SINS 79 



lytic action of this normal goat serum, these 

 experiments of Ehrlich and Morgenroth show 

 us four substances, viz., two inter-bodies and 

 two complements. This at once makes clear the 

 opposing views of these authorities. According to 

 Ehrlich, however, the number of active substances 

 in normal serum is still greater, for it often hap- 

 pens that a specific inter-body shows itself to be 

 made up of several inter-bodies, all, to be sure, 

 fitting the same specific red cell, but differing 

 from each other by their behavior toward dif- 

 ferent complements. Ehrlich, therefore, regards 

 the substances concerned in haemolysis which 

 occur in normal serum to be of great number and 

 variety. 



Difference between a Normal and a Specific 

 Immune Serum. Practical Application. Return- 

 ing now to the question of the difference between a 

 specific immune serum and a normal one, we find 

 this to be as follows : Normal serum contains a great 

 variety of inter-bodies, in very small amounts, and a 

 considerable amount of complements. In immune 

 serum, on the other hand, the amount of a specific 

 inter-body, the one which fits the haptophore group 

 of a certain cell, is enormously increased. This 

 specifically increased inter-body, it will be remem- 

 bered, is called the immune body. The comple- 

 ment, as shown by v. Dungern, Bordet, Ehrlich 

 and Morgenroth and Wassermann, is in no way 



