SYPHILIS 129 



and i in 1,000, in normal saline. With each of these dilutions 

 prepare sensitized sheep corpuscles by taking- i part of the 

 thrice-washed corpuscles and 4 parts of the diluted ambocep- 

 tor, and mix. Now add i volume of each mixture to the diluted 

 human serum of course, in an incubator and watch the 

 result, stirring once or twice. This will enable you to deter- 

 mine, roughly, the amount of anti-sheep serum necessary for 

 the complete sensitization of the corpuscles, and in the actual 

 test it should be used about twice as strong*. Thus, if there 

 were complete haemolysis with the serums in dilutions of i in 

 200, 400, 600, and 800, and none, or only a trace, at i in 1,000, 

 the serum should be used at a dilution of i in 400, or there- 

 abouts, i.e., 2 or 2\ times as strong as the minimum amount 

 giving- complete haemolysis. 



These preparations being made, the test is simple. It is, 

 however, much slower than the previous method, the reason 

 being that the great dilution of the anti-sheep serum prac- 

 tically throws the agglutinin out of action, so that the cor- 

 puscles settle very slowly. I think, also, that the method is 

 less sensitive than that in which human corpuscles are used. 



On the whole, as stated above, I advise practitioners against 

 attempting their own Wassermann reactions, unless they are 

 possessed of a considerable amount of technical skill, and 

 have more time to spare than is usually the case. I advise 

 also against attempting any methods dependent on materials 

 dried on filter-paper, etc., or indeed any process in which the 

 reagents used cannot be frequently standardized. 



INTERPRETATION OF THE RESULTS OF THE WASSERMANN 

 REACTION. 



This is of vital importance to all practitioners, and ignor- 

 ance of it is constantly leading- to ^mistakes. The following 

 epitomizes the author's experience in a large number of 

 cases : 



1. In the primary stage there is usually a positive reaction 

 as soon as there is definite infiltration of the chancre, but 

 occasionally it is delayed longer. The method of choice in 

 the diagnosis of a doubtful chancre is the search for 

 spirochaetes. If the Wassermann reaction is positive, it is 

 conclusive ; if negative, the case may be syphilis, and it should 

 be re-examined in a few days. 



2. In the secondary stage practically all cases give a posi- 



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