554 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



animal into a normal one. While there is reason for assuming that it is the 

 "sessile" antibodies, those localized in certain cells and tissues, which are re- 

 sponsible for the anaphylactic reaction taking place in contact with the anti- 

 gen, at the same time these antibodies may also be circulating in the blood and 

 can then be transferred to another individual ; in the latter these specific 

 antibodies again may attach themselves to certain cells and tissues and render 

 them hypersensitive to the action of the specific antigens. Similarly, in 

 idiosyncrasy it is possible to transfer this condition passively in many, al- 

 though not in all cases, by injecting a small amount of blood serum of an 

 idiosyncratic person intracutaneously into a normal one. If on the following 

 day the antigen is re-injected into the same place of the skin, a marked 

 reaction, indicating hypersensitiveness of the treated tissue, appears. This is 

 the Prausnitz-Kiistner reaction. This reaction is positive especially in the 

 transfer to other persons of human blood serum from individuals hyper- 

 sensitive to plant pollen, egg white, cow's milk, fish, or horse dander. On the 

 other hand, injection of the serum from cases of drug idiosyncrasy does not 

 lead to passive transfer of the hypersensitive state. The blood serum of the 

 hypersensitive donor, in whom the Prausnitz-Kiistner reaction is positive, 

 contains an antibody, reagin, which can combine with the tissue of a normal 

 person, into whom it has been introduced, and make this tissue hypersensitive. 

 Such serum, or rather the antibody which it contains, may also bind comple- 

 ment when mixed with the specific antigen (allergen), or it may neutralize 

 the latter. It has been possible to accomplish passive transfer of such anti- 

 bodies also in the guinea pig. For this purpose it is necessary to inject larger 

 quantities of the blood serum ; the antibodies again become sessile in certain 

 instances and induce hypersensitiveness. However, the number of cases of 

 idiosyncrasy in which this last named procedure has succeeded is much 

 smaller than that in which a transfer from man to man could be accomplished 

 by the Prausnitz-Kiistner method. It seems that the passive transfer of idio- 

 syncrasy succeeds better if the serum containing the antibody is obtained 

 from animals nearly related to those which are to be passively sensitized. 

 On the other hand, if the serum which serves as carrier comes from a more 

 distant species, then it is liable to elicit the production of neutralizing im- 

 mune substances in the injected animal. 



There is an additional method which allows the passive transfer of hyper- 

 sensitiveness, although in a much more restricted sense. It has been shown by 

 Naegeli, de Quervain and Stalden, in a case of hypersusceptibility of the skin 

 to antipyrin, in which the skin was sensitized not throughout the body but 

 only in certain areas, that following autotransplanatation of a piece of the 

 hypersensitive skin to a place where the skin was normal, the transplant 

 retained its hypersensitiveness in the new situation. It may be concluded, 

 therefore, that the hypersensitiveness actually resides in the tissues, and in 

 vitro experiments in which the skin was exposed to the influence of anti- 

 pyrin, it could be shown that it was the epidermal cells in which the specific 

 changes had taken place ; these responded to contact with this substances 

 with solution processes. We have, therefore, to deal in instances such as this, 



