PRODUCTION OF HJEMOLYTIC AMBOCEPTORS. 243 



The extraordinary multiplicity of such dissolved substances in 

 blood serum has already been pointed out by Ehrlich. 1 "The chief 

 tools of the internal metabolism are the receptors of the first, second, 

 and third order. They are constantly being used up and produced 

 anew, and can readily therefore, when overproduced, get into the 

 circulation. Considering the large number of organs and the com- 

 plexity of the protoplasm's chemistry it need not be surprising if 

 the blood, the representative of all the tissues, is filled with an infinite 

 number of the most diverse receptors. Of these we have thus far 

 learned to distinguish the various kinds of lysins, agglutinins, coagu- 

 lins, complements, ferments, antitoxins, anticomplements, and anti- 

 ferments." 



These free receptors when injected into a suitable foreign animal 

 species should therefore show their identity with those of the cells 

 by the fact that, like the latter, they produce immune bodies identical 

 with those produced in the usual way. 



A few isolated observations have been made in this direction,, 

 but the conclusions following therefrom according to the theory have 

 not been drawn. Thus v. Dungern 2 has observed the development 

 of a haemolysin directed against chicken erythrocytes as a result of 

 injections of chicken serum into guinea-pig serum, and Tschistovitsch 3 

 has observed the formation of a haemolysin (besides agglutinins) on 

 injecting rabbits with horse serum. 4 



For some time past I have made experiments of this kind to demon- 

 strate the existence hi goat serum of free receptors identical with 

 receptors of goat erythrocytes. These studies were prompted by 

 the observation that a few normal goat sera exerted a slight inhibiting 

 action on the amboceptors of rabbits immunized with ox blood, an 

 action which Ehrlich and Morgenroth had shown to be due to an 

 anti-immune body. 5 I am led to publish these experiments now 



then functionate as anti-immune bodies. See Ehrlich and Morgenroth, pages 

 23 and 88. 



1 Ehrlich, Schlussbetrachtungen, 1. c. 



2 v. Dungern, Munch, med. Wochenschr. 1899. 



3 Tschistovitsch, Annal. Inst. Pasteur, 1899. 



4 The increase in haemolytic action of rabbit serum for chicken blood after 

 the injection of chicken blood-plasma, described by Xolf (Annal. Inst. Pasteur, 

 1901), rests apparently only on an increase of complement, not on the develop- 

 ment of new amboceptors. 



6 See pages 88 et seq. 



