124 PREC1PITINS 



reaction since it was first recommended. According to the most recent publication, 

 the reaction is carried out as follows: 

 The requirements are: 



1. One per cent, solution of sodium glycocholate (Merck) in distilled water. 



2. The patient's serum which must be absolutely clear, and heated for one-half an 

 hour at 56 C. 



Two-tenths of each of the above are placed into a narrow test-tube 6 to 7 mm. in 

 diameter, and allowed to rest for sixteen to twenty hours at room temperature. A 

 positive reaction consists of the appearance of distinct coarse flocculi, which as a rule, 

 collect near the surface. Mere turbidity or faint precipitates are considered as 

 negative. 



The original Forges method of employing lecithin was not at all specific, the reac- 

 tion being present in tuberculosis, carcinoma, and other infectious diseases. As for 

 the new modifications, nothing has been brought forward in their support. 



This reaction belongs to the same general class of precipita- 

 Klausner's tion tests for lues, but is very much simpler than any of the 

 Reaction, others. Two- tenths c.cm. of absolutely clear, fresh (at the 

 most, two hours old), active serum is mixed with 0.6 c.cm. of 

 distilled water, in a small test-tube 7X0.5 cm. Sera containing hemo- 

 globin or lipoids are not suitable for this reaction. The mixtures are al- 

 lowed to stand at room temperature. In several hours, at the latest 

 fifteen, a thick flocculent precipitate 2 to 4 mm. high appears at the 

 bottom of the tube. Kreibich's analysis showed it to consist of fibrin 

 globulin. 



Apparently this substance is increased in luetic serum and precipitated by the dis- 

 tilled water in which it is insoluble. Klausner's reaction is by no means specific for 

 syphilis as it is in evidence in starvation, typhoid fever, measles, scarlet fever, pneu- 

 monia, and other diseases, as well as during health. Nevertheless it must be said 

 that it is found more frequently, earlier and much stronger in lues than in any other 

 condition. 



Klausner states that in fresh cases of lues the best reaction is seen in about seven 

 to nine hours, while in older cases a weak reaction appears in twelve hours. Mercury 

 influences the test in that the interval until the precipitate becomes marked, is pro- 

 longed and later on the precipitate becomes fainter. 



In spite of its simplicity, Klausner's reaction has not been generally adopted 

 for clinical work, as the Wassermann reaction with its far greater accuracy has re- 

 placed it. 



Proteid Precipitins. 



While bacterial precipitation is interesting from a biological standpoint 

 but bears no practical significance, proteid precipitation represents one of 

 the most important practical aids in forensic medicine. By this means the 

 differentiation of various proteids can be easily and definitely determined, a 

 problem which was left unsolved by chemistry. 



The phenomenon of protein precipitation is absolutely analogous to 



