130 PROTEIN THERAPY 



elaborated during the course of the past ten years. Not only was the 

 luetin reaction found to be unreliable when iodids were administered 

 but even with these excluded the specificity of the reaction is by no 

 means to be depended upon. Thus Blechmann has but recently pub- 

 lished a series of 80 cases in which he injected luetin. In this group 

 of children his luetin was positive in about 35% of the congenital 

 luetics, while in about 40% of nonluetic children he also obtained a 

 positive luetin test. So, too, the typhoidin reaction has been found an 

 absolutely unreliable index of the immunity of the patient. Other 

 skin reactions, such as the gonococcus reaction, the placental reaction 

 for pregnancy and the pneumococcus reaction, have failed for the same 

 reason. Only where we deal with a disease depending very probably 

 on a definite hypersensitizatlon of the patient, such as in asthma, are 

 the skin reactions useful. 



When skin reactions are under consideration one inevitably thinks 

 of the tuberculin (either the v. Pirquet or the intracutaneous test) 

 reaction as the most typical and best known of the whole group. The 

 general reaction subcutaneous injection should by no means be 

 considered in the same category. It is very probable that the tuber- 

 culin reaction, which for ordinary clinical purposes we may consider 

 specific, has a very large element of nonspecificity in its mechanism 

 much larger than is ordinarily considered probable, as has been fully 

 discussed in the chapter on The Focal Reaction. Such a phenomenon 

 would by no means be an anomaly in medicine; indeed our Wasser- 

 mann reaction is an example of just this same condition. Elaborated 

 on a theory of strict specificity it has resolved itself into a specific 

 clinical test that is based on a physical mechanism in which the anti- 

 gen-antibody reaction plays no part. We must recognize, too, that the 

 evanescent reactions or wheals that we observe in determining sensi- 

 tization to proteins (asthma, etc.) are fundamentally different in many 

 respects from the tuberculin reaction. 



Clinically it has been determined that from the time of the birth 

 of the individual the organism begins to alter in its reactivity of the 

 skin. At first negative to tuberculin, the reactivity increases pro- 

 gressively with the age of the individual until in adult life a maximum 

 is reached and maintained quite consistently except for certain periods 

 of depression, some of which have been previously mentioned. But 

 during this period the skin does not only become sensitive to tuber- 

 culin, but increasingly sensitive to a series of other bacterial and plant 

 proteins and extractives; so to colon and dysentery and cholera pro- 

 teins, to bacterial toxins, peptones, etc. We deal obviously with a 

 more or less general "sensitization" or "Umstimmung" or "allergy," as 

 we may choose to term the condition. 



Now, this allergy may be a more or less specialized property of the 

 skin, indeed may be localized in certain areas of the skin. As a result 

 of it the tissues acquire the ability to react more energetically and 



