IDIOSYNCRASY AND ANAPHYLAXIS 555 



primarily with a hypersusceptibility of epidermal cells rather than of blood 

 vessels. On the other hand, it is the latter which are essentially affected in 

 cases in which urticaria develops rapidly following the application of a sub- 

 stance towards which a person shows an idiosyncrasy. 



A number of years ago the writer investigated this question as to whether 

 a piece of uterus, which has been sensitized to horse serum through a pre- 

 vious injection of this substance into a guinea pig, would elicit a more rapid 

 and a more intense lymphocytic infiltration than a non-sensitized piece of 

 uterus after homoiotransplantation into a non-sensitized guinea pig, when 

 the latter was injected with horse serum following transplantation of the 

 piece of tissue. The result was negative ; the response of the host to the trans- 

 planted piece was not altered. It seems, then, that the chemical change under- 

 lying hypersensitiveness does not increase the reaction characteristic of 

 homoiotransplanation. Somewhat similar are the recent observations of 

 Aronson, who found that if a guinea pig is made hypersensitive to horse 

 serum, the spleen and bone marrow of this animal have not thereby become 

 particularly sensitive to the effects of horse serum if the latter is added in 

 vitro, although the injection of horse serum into the skin of the intact 

 animal would elicit the Arthus phenomenon. On the other hand, if a guinea 

 pig has been infected with tubercle bacilli, its tissues are readily injured 

 through addition of tuberculin, either in vitro (Rich and Lewis; Aronson), 

 or after homoiotransplantation (Pagel). 



So far, we have referred to substances strange to the body as exciting 

 factors in the production of idiosyncrasy. Is it possible that also autogenous 

 substances, those originating in the same individual, may cause sensitization? 

 Observations indicating such an occurrence are on record. Thus Duke found 

 that in several cases, in which, following pregnancy, milk was retained in 

 the breast or in which lactation was much prolonged, a state of hypersensitive- 

 ness to the autogenous milk developed. Injection of the patient's milk into 

 the skin not only gave rise to local skin reactions, but also to asthmatic 

 attacks. Furthermore, the hypersensitiveness could be transferred by the 

 Prausnitz-Kustner method to other normal persons, but it was only human 

 milk, and not cow's milk, which elicited these reactions, indicating that in 

 all probability an organismal (species) differential was involved in this 

 condition. Milk does not, under normal conditions, circulate in the body- 

 fluids and is, therefore, strange to the central organ-systems of the body; 

 hence the occurrence of an autogenous sensitization is understandable under 

 such circumstances. Furthermore, there is reason for assuming that here 

 an inherited predisposition to such a sensitization may play a certain role. In 

 this connection we may again refer to the experiments of Guyer, who believes 

 that in the rabbit precipitating antisera can be formed against lens substance 

 through injury to the animal's own lens, and to the corresponding experiments 

 of Henshaw, who found that it is possible in the guinea pig to produce sensitiz- 

 ing antibodies of an autogenous nature by the application of ultra-violet 

 radiation to the skin. 



As already mentioned, non-protein substances in combination with serum 



