364 INFECTION AND IMMUNITY 



This explanation of Wells seems to us eminently logical. We 

 would add to it only the following consideration. Acute death may 

 well be caused directly by the acute spasm of smooth muscle tissue, 

 and the acute pathological manifestations may be dependent upon 

 the distribution of such muscle. This does not, however, exclude 

 the likelihood that severe anaphylactic injury may be caused in 

 other cells in the body as well, but these, not being able to react 

 by acute contraction, or by any other pathological alteration that 

 can cause acute and sudden death, may still be injured severely 

 without there being an immediately noticeable effect. 



ANTI-ANAPHYLA.XIS. When sensitized animals recover from 

 anaphylactic shock, they do not react to a subsequent injection of 

 the same substance made within a reasonable interval. 



This desensitization or ' ' antianaphylaxis ' ' as Besredka and 

 Steinhardt 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, 

 anaphylaxis 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 manner to lose their antianaphylaxis within three weeks. 



It is not at all necessary to actually shock an animal to desen- 

 sitize it. The doses may be given gradually, either in small frac- 

 tions or slowly by means of high dilution, as by the method of 

 Friedberger, and gradual desensitization thereby accomplished 

 without noticeable harm.. This is of great practical importance. 



Desensitization in the ordinary sense probably means a gradual 

 saturation of the sessile antibodies with antigen. It can be demon- 

 strated not only in the living animal but upon the sensitive uterus 

 in the Dale apparatus. 



Another form of partial protection against anaphylaxis, by the 

 injection of large amounts of specific antiserum has been mentioned 

 above. The mechanism of this is obvious. 



Desensitization by injection into the rectum or by feeding has 



