SYPHILIS 105 



adopted is as follows : Prepare a series of dilutions of fresh 

 normal serum with normal saHne solution in the proportion of 

 I to 4, as before. Prepare also dilutions of the anti-sheep serum 

 of I in 200, I in 400, i in 600, i in 800, 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 serum, and mix. Now add i volume of 

 each mixture to the diluted human serum — of course, in an incu- 

 bator — and watch the result, stirring once or twice. This will 

 enable you to determine, roughly, the amount of anti-sheep serum 

 necessary for the complete sensitization of the corpuscles, and in 

 the actual test it should be used nearly twice as strong. Thus, if 

 there were complete hasmolysis 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 thereabouts. 



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

 ever, much slower than the previous method, the reason being 

 that the great dilution of the anti-sheep serum practically throws 

 the agglutinin out of action, so that the corpuscles 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 ignorance of 

 it is constantly leading to mistakes. The following epitomizes 

 the author's experience of over three years in a large number 

 of cases : 



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

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

 sionally it is delayed longer. The method of choice in the diag- 

 nosis of a doubtful chancre is the search for spirochaetes. If the 

 Wassermann reaction is positive, it is conclusive ; if negative, 



