PROPERTIES OF ANTISENSITIZERS. 283 



of the antiserum as a preventive, the sensitizer being neutralized 

 before it has affected the corpuscles. 



We may also attempt to "cure" corpuscles already treated with 

 the sensitizer by means of the antiserum. Attempts of this sort 

 have been made by Pfeiffer and Friedberger,* who worked with 

 bacteria instead of blood corpuscles. Such experiments are also 

 similar to those of Madsenf and Kraus and Lipschiitz,t who cured 

 blood cells intoxicated with bacterial poisons by means of antitoxins. 



This second method of experimentation has seemed to us prefer- 

 able. It allows one to treat a single sensitizer with the antiserum 

 to the exclusion of other sensitizers. In addition to the specific 

 sensitizer in rabbit > ox serum there are one or, according to 

 certain authors, a large number of similar normal sensitizers already 

 present in the animal before immunization. If we begin by mix- 

 ing the antiserum with rabbit > ox serum, it is probable that the 

 normal sensitizers will take part in the reaction. But if, instead, 

 we first mix the sensitizing serum with the corpuscles and then 

 wash them to remove the excess of serum, and add them, laden as 

 they are with the specific substance, to antiserum, the latter should 

 affect only the specific sensitizer united with the blood cells. 



It remains to choose a suitable alexin, which should be one that 

 is not destroyed or weakened by the antiserum. The simplest thing 

 is to employ fresh guinea-pig serum, as this is the species of animal 

 that furnishes the antiserum. Not only is this alexin not affected 

 by the antiserum, but it acts very well in conjunction with the 

 sensitizers employ ed. 



Following is the method of demonstrating antisensitizing action : 



Sensitized blood, and also control non-sensitized blood, are first 

 prepared. In each of two large tubes is placed 1 c.c. of washed 

 bovine blood. || To tube A is then added 2 c.c. of rabbit > ox 



* Centralblatt fur Bakt. Orig., XXXIV, 72. 



t Zeitschrift fur Hygiene, XXXII. 



J Idem, XLV, 49. 



Human alexin may also be used. 



|| This washed blood has been restored to its original volume, that is to say, 

 contains as many red blood cells to a given volume as did the original blood. A 

 small amount of defibrinated blood is poured into a tube and the level marked on 

 the glass. After filling with salt solution and centrifugalization, the supernatant 

 fluid is removed and sufficient salt solution added to restore the sediment to its 

 original volume. 



