444 INFECTION AND RESISTANCE 



but will show a reaction when the second application is made sub- 

 cutaneously. Negative evidence pointing in the same direction is 

 the observation that absolutely no influence is exerted upon the out- 

 come of tuberculin reaction if the tuberculin is previously mixed 

 with blood serum from either positively or negatively reacting 

 cases. 53 This would tend to show that, whether reacting or not, the 

 factors which determined this are certainly not present in the cir- 

 culating plasma. 



That the circulation of tubercle antibodies in the blood may even 

 interfere with the localized tuberculin reaction is rendered likely by 

 the fact that skin reactions are often negative in cases of advanced 

 tuberculosis, and that, as we are told by Dr. Blair, of the N. Y. 

 Zoological Park, such reactions are usually negative in tuberculous 

 monkeys in which the disease is invariably very rapid and acute. 



PRACTICAL DIAGNOSTIC USES OF ANAPHYLAXIS 



*The specificity of the anaphylactic reaction has led to extensive 

 attempt to utilize it for forensic protein determinations in the same 

 way in which the precipitin test is used. Uhlenhuth, 54 Thomsen, 55 

 Pfeiffer, and others have carried on extensive experimentation in 

 this problem, the technique, in general, consisting in sensitizing 

 guinea pigs with solutions of the unknown protein (dissolved blood 

 spots, etc.) and testing them by a second injection of the suspected 

 protein after the usual anaphylactic incubation time. The results of 

 such work have shown that indeed positive reaction may be obtained 

 and diagnosis made in this way. However, the reactions are not ordi- 

 narily very striking, and this method is not as reliable as the precipi- 

 tin method. Uhlenhuth 56 believes that the anaphylactic reaction 

 has value only in cases in which the amount of unknown protein is so 

 small or so changed by preservation or decomposition that its pre- 

 cipitable qualities have been lost. 



Yamanouchi's 57 attempt to utilize anaphylaxis for the diagnosis 

 of tuberculosis, by passively sensitizing guinea pigs with the serum 

 of tuberculous patients and testing subsequently with tuberculin, has 

 been mentioned before. Although he claims positive experiments, 

 our own experience with a similar technique has given us results 

 which were so irregular that we feel that this technique has very 

 slight practical value, if any. 



Pfeiffer 58 has attempted to apply anaphylaxis to the diagnosis 



53 V. Pirquet. Loc. cit. 



54 Uhlenhuth. Deutsche milit. Zeitschr. No. 2, 1909. Cited from same 

 author, Zeitschr. f. Immunit'dtsforsch., Vol. 1, 1909. 



55 Thomsen. Zeitschr. f. Immunitatsforsch., Vol. 1, 1909. 



56 Uhlenhuth. Zeitschr. f. Immunitatsforsch., Ref. Vol. 1, 1909, p. 525. 



57 Yamanouchi. Wien. klin. Woch., No. 47, 1908. 



58 Pfeiffer. Zeitschr. f. Imm., Vol. 4. 1910. 



