300 . INFECTION AND IMMUNITY 



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This desensitization or " antianaphylaxis " as Besredka l and Stein- 

 hardt have called it, appears immediately after recovery from the second 

 injection. Antianaphylaxis may also be produced if animals which have 

 received the first or sensitizing dose are injected with comparatively 

 large quantities of the same substance during the preanaphylactic period 

 or, as it is sometimes spoken of, during the anaphylactic incubation 

 time. This injection should not be done too soon after the first dose, but 

 rather toward the middle or end of the preanaphylactic period. 



If given within one or two days after the sensitizing injection, ana- 

 phylaxis will develop, nevertheless. The desensitized condition is a 

 purely transitory state. Besredka and Steinhardt believe that it lasts 

 a long time, while Otto found guinea-pigs immunized in the above man- 

 ner to lose their antianaphylaxis within three weeks. 



An important development was achieved when Nicolle, Otto, 2 Gay 

 and Southard, 3 and others 4 showed that the hypersusceptible state 

 could be passively transferred to normal animals by injecting them with 

 the serum of anaphylactic animals. In such experiments the serum of 

 the anaphylactic animal is first injected in quantities of 0.5 c.c. or prefer- 

 ably more, and twenty-four hours later an injection of the specific anti- 

 gen -that is, the proteid used for sensitization is given. The animals 

 so treated show typical symptoms of hypersusceptibility and often die. 



Simultaneous inoculation of the two substances, either mixed or in- 

 jected separately, does not produce the same effect. On this point, 

 however, there is not complete unanimity, since Weill-Halle and Le- 

 maire 5 report aphylactic symptoms in guinea-pigs hypersusceptible to 

 horse serum. A fact, observed by Otto, is that the serum of guinea-pigs 

 who have been given the sensitizing or first injection will confer passive 

 anaphylaxis on the eighth or tenth day after injection, before the ani- 

 mals themselves show evidences of being actively hypersensitized. It 

 is also true that occasionally the serum of antianaphylactic animals will 

 possess the power of conferring passive anaphylaxis. 



Anaphylaxis may be transmitted by inheritance. Thus the young 

 of anaphylactic guinea-pigs show hypersusceptibility, irrespective of 

 whether the mother became hypersusceptible before or after the be- 

 ginning of pregnancy. Such anaphylaxis has no reference to the con- 

 dition of the father, and is not transmitted by the milk. 



1 Besredka and Steinhardt, Ann, de 1'Inst. Pasteur, 1907. 



2 Otto, loc. cit. z Gay and Southard, loc. cit. 

 4 Weill-Halle and Lemaire, Compt. rend, de la Soc. de Biol,, 1907. 



6 Nicolle, Ann. de ITnst. Pasteur, 1907, 1908. 



