PROTEIN SENSITIZATION OR ANAPHYLAXIS 255 



at that time were obtained by injecting the anaphylactic 

 serum intraperitoneally and the antigen intravenously, 

 twenty-four hours later. Later it was shown by Doerr 

 and Russ, also by Biedl and Kraus, that acute symptoms, 

 with death, may result from the simultaneous intravenous 

 injection of anaphylactic serum and antigen. There is 

 therefore no period of incubation in passive anaphylaxis, 

 and this condition loses much of the theoretical importance 

 which was attached to it so long as it seemed to require a 

 period of incubation for its development. As we shall see 

 later, the serum and organ extracts of sensitized animals 

 mixed in vitro in proper proportions with the antigen produce 

 a poison which kills fresh animals in anaphylactic shock. 



It has been found by Gay and Southard that 0.1 c.c. of 

 serum suffices to render the recipient passively anaphylactic. 



In reference to passive homologous anaphylaxis in rabbits, 

 Friedemann 1 makes a statement of which the following is 

 a summary: Among the old authorities, Weichard with 

 a mixture of placental cells and the antiserum, Batelli 

 with laked blood and the corresponding hemolysin, and 

 Nicolle with horse serum and anti-horse serum, succeeded. 

 More recent authorities 2 have failed to secure passive 

 homologous anaphylaxis in rabbits. The divergencies are 

 probably explained by Friedemann, who recommends the 

 following: (1) Antigen and antiserum should be injected 

 intravenously and simultaneously. When the antigen is 

 introduced twenty-four hours after the serum there is no 

 marked reaction. (2) There is an optimum proportion 

 between anti-serum and antigen. By employing 2.5 c.c. 

 of anti-serum, Friedemann obtained no results when the 

 antigen varied from 2.5 to 0.25 c.c., but did obtain positive 

 effects when the amount of antigen was reduced to from 

 0.025 to 0.0025 c.c. 



This corresponds exactly with our researches on anaphyl- 

 axis in vitro (see p. 274). 



1 Jahresbericht u. d. Ergeb. d. Immunitatsforschung, 1910, vi, 67. 



2 Braun, Kraus, and others. 



