HYPERSUSCEPTIBILITY 361 



anaphylactic antibodies, separate from precipitins, opsonins, etc., 

 etc. ; Friedberger, 34 himself, from the beginning, identified them with 

 precipitins. The direct quantitative relationship between pre- 

 cipitating antibodies and the power to convey passive sensitization. 

 described by Doerr and Russ 35 would point in the same direction 

 as would the above mentioned experiments of Weil. Since we have 

 variously expressed in the preceding pages our own opinion that 

 all antibodies developed against a single antigen are one and the 

 same substance, we have no hesitation in stating that we think that 

 the so-called sensitizing antibody is identical with the sensitizing 

 antibody which is formed to the antigen, rendering it amenable to 

 agglutination or precipitation or complement-fixation. 



Where Does the Reaction Occur. As we have seen, when the 

 antigen and antibody are injected simultaneously or within a very 

 short period of one another, no anaphylactic symptoms occur. The 

 study of this interval has gradually led to the recognition that 

 the anaphylactic reaction, whatever it may be, takes place upon the 

 body cells and that the interval in passive sensitization is neces- 

 sitated by the time required for the anchoring of the antibodies 

 to the cells of the tissues. Experiments by Pearce and Eisenbrey 36 

 (1910) showed definitely that a hypersusceptible dog remained sen- 

 sitized even when his entire blood volume was substituted with that 

 of a normal dog. The principle has been made especially clear by 

 the introduction of direct methods of observation of the smooth 

 muscle cells of animals, by Schultz 37 and by Dale, 38 a method which 

 has been particularly developed by Weil. 39 It seems fairly clear 

 from this work and a volume of other researches which cannot be 

 reviewed here, that acute protein anaphylaxis as we see it in guinea- 

 pigs and other laboratory animals is due to the direct reaction 

 between antigen and a specific antibody when this reaction takes 

 place upon the body cells and not in the blood stream. Just how 

 much influence the reaction within the blood stream can exert or 



34 Friedberger, with Hartoch, Zeit. f . Immunit., 3, 1909. 



35 Doerr and Buss, Zeit. f. Immunit., 3, 1909. 



36 Pearce and Eisenbrey, Congr. Am. Phys. and Surg., 1910, viii. 



37 Schultz, Jour. Pharmacol. and Exper. Therap., 1910, i. 



38 Dale, Jour. Pharmacol. and Exper. Therap., 1913, iv. 



39 Weil, Jour. Med. Eesearch, 27, 1913; 30, 1914; Proc. Soc. Exper. Biol. and 

 Med., 1914, xi, 86. 



