135 



formation can be absolutely checked and that in a much weaker 

 solution of the serum than that in which (without addition of 

 one of the mentioned albumina) fibrine alone is no longer 

 transformed. 



Moreover I took care in my experiments that the surface of 

 the uncoloured albumen was no larger than that of the fibrine. 

 With an increasing digestion-surface the intensity of the diges- 

 tion-process also increases. With this factor we must however 

 reckon in order to explain the checking action of fibrine. For 

 tuberculine contains a dissoluted albumen, viz. of the character 

 of an albuminoid. 



As albuminoid is again easier to digest than ordinary albumen 

 (e.g. hen's albumen) and the surface of tuberculine is so large 

 because of its dissoluted state, the checking influence of this 

 substance upon the transformation of coloured fibrine is therefore 

 so great. And especially greater than that of hen's albumen. 



By a simple experiment may be indicated that each serum 

 easily transforms tuberculine. For if we allow any serum to 

 act upon tuberculine for 3 hours in a temperature of 37° C, 

 and if we only then add the fibrine, no or nearly no fibrine, 

 is transformed. If we place serum in the incubator for 3 hours 

 in a temperature of 37*^ C, this has nearly no influence on 

 the transformation of fibrine, then added. Probably this simple 

 experiment also sufficiently explains why every man finally 

 reacts upon an injection of a very large dose of tuberculine 

 (more than 10 mG.) The quantity of tuberculine is so great 

 that only by the action of the peptic ferment occurring in every 

 human serum enough transformation-products can be formed 

 to cause temperature rises, etc. 



A new method of serological research. 



All these preparatory researches were necessary clearly to 

 understand the now to be treated new serological method. 



For soon it appeared to me that tuberculine, added to the 

 blood-serum obtained from a sufferer from tuberculosis less 

 checked the fibrine-transformation than when added to non- 

 tuberculous serum. This I found repeatedly confirmed. Conse- 

 quently : If the fihrolytic power of 2 sera, the one obtained 



