7 IMMUNE SERA. 



suspected blood solution, and in a fourth some of 

 the specific serum, both without any additions. 

 All four tubes are placed in an incubator at 37 C. 

 for one hour or are left at normal room temperature 

 for several hours. If the clot be that of human 

 blood, the first tube must show distinct evidences 

 of precipitation, while all the control tubes must 

 have remained clear. This reaction is absolutely 

 specific, with one exception, as was pointed out by 

 the author, Schutze, and Stern. A serum derived 

 by treating an animal with human serum reacts 

 also to the serum of monkeys. It does not, how- 

 ever, react to the sera of any other animals thus 

 far investigated. This method, then, furnishes 

 the surest differential diagnosis for forensic pur- 

 poses, as has been proved by the researches into the 

 subject by Ziemke. 



The Method Applied to Distinguish Albumins. 

 The A. Wassermann method of diagnosis by means 

 of precipitins has found further application. Le- 

 blanc showed that the serum of an animal treated 

 with pseudo-globulin causes a precipitate only in a 

 solution of pseudo-globulin; one derived from an 

 animal treated with serum albumin, only in a solu- 

 tion of serum albumin; one derived by treatment 

 with haemoglobin, only in a solution of haemoglobin, 

 etc. One is enabled, therefore, by this method to 

 distinguish the different albuminous bodies. Le- 

 clainche and Vallee as well as Mertens showed by 

 this method that the albumins of blood and milk 



