96 IMMUNITY AND ANAPHYLAXIS 



If the dose of albumin injected is strictly equivalent or 

 less than the dose of normal affinity every antigen injected 

 will be fixed by normal antibody, digested, assimilated or 

 eliminated and the organism will reproduce and multiply 

 this normal affinity-antibody which then will become the 

 antibody in excess. If the injected dose of albumin is 

 greater than the dose of normal affinity the antigen will fix 

 itself to the normal antibody en surcharge and the organism 

 will suffer or rather the antigen in excess will circulate in 

 the blood up to the time when the organism can produce a 

 quantity of antibody sufficient to fix and digest this excess 

 of antigen. It is only after a total disappearance of antigen 

 that the antibody in excess will appear. 



In this way is explained quite easily a fact which until 

 now has seemed inexplicable. We know that if a small 

 injection of antigen causes an excess of antibody and the 

 anaphy lactic state to appear in ten to fifteen days, the injec- 

 tion of a large quantity of the same antigen into an animal 

 of the same species will produce the same effect only after 

 an incubation period of some weeks or even months simply 

 because the existence of an excess of antigen in the circula- 

 tion excludes the possibility of the simultaneous existence 

 of an excess of antibody in the organism. 



More recently, however, Longcope and Rackemann 1 have 

 been able to demonstrate that in the serum disease, which as 

 originally shown by Von Pirquet and Schick 2 often follows 

 the injection of antitoxic or antibacterial serum in man, 

 there may be a coexistence of antigen and antibody in the 

 circulation. 



Working with cases of pneumonia, which had been treated 

 with antipneumococcus serum obtained from horses, they 

 found that the horse serum persisted unchanged in the blood 

 for several days, and that in a few cases circulating antibody 

 could be demonstrated in the same specimen of patient's 

 blood serum in which horse serum could also be demon- 



- x The Relation of Circulating Antibodies to Serum Disease, Jour. 

 Exp. Med., 1918, xxvii, 341. 



2 Die Serumkrankheit, Leipsic and Vienna, 1915. 



