METHODS FOR CONDUCTING THE SYPHILIS REACTION 435 



first, by the serum and antigen alone, and second by these two sub- 

 stances combined. The complement absorbed is measured in terms 

 of hemolytic doses. This method consumes a little more time and 

 more of the various reagents is required. It is, nevertheless, the 

 best quantitative method we have, and shows exactly the degree of 

 complement fixation in each case. 



In conducting any complement-fixation test the following are 

 essential factors if success is to be achieved: (1) Reliable reagents, 

 particularly a good antigen must be had, for no matter how much 

 care is exercised, good results cannot be secured with indifferent 

 reagents; (2) the observer must possess a thorough working under- 

 standing of the underlying principles and particularly of the quanti- 

 tative relations of the various reagents; (3) there must be an accurate 

 adjustment of the hemolytic system; (4) he must have a careful, 

 painstaking and accurate habit of pipeting small amounts. Accuracy 

 should never be sacrificed for speed, as the latter is properly acquired 

 only with experience. 



TECHNIC OF THE FIRST METHOD 



This is the original Wassermann reaction, except that an alcoholic, 

 instead of an aqueous extract of syphilitic liver, is used as antigen, 

 and the amounts of each reagent are just one-half those originally 

 employed. This is the simplest of all technics and, when properly 

 performed, constitutes, in the final analysis, a reliable test and one 

 especially adapted for those not constantly engaged in this work. 



1. Complement. Fresh clear serum (not over twenty-four hours 

 old) of a healthy guinea-pig. Dilute 1:20 by adding 19 c.c. of sterile 

 normal saline solution to each 1 c.c. of serum. Dose, 1 c.c. ( = 0.05 

 c.c. of undiluted serum). 



2. Corpuscles. Sheep's blood washed three times and diluted 

 to make a 2.5 per cent, suspension. For example, 1 c.c. of corpuscles 

 in 39 c.c. of salt solution makes up sufficient for a number of tests. 



3. Hemolytic Amboceptor. Serum of a rabbit immunized with 

 washed sheep's corpuscles. As stated elsewhere, this serum is heated 

 to 55 C. for half an hour, and an equal part of chemically pure 

 glycerine is added. Mix well and preserve in sterile 1 c.c. ampules. 

 Each ampule will, therefore, contain 0.5 c.c. of serum. One stock 

 dilution is prepared in such manner that about 0.2 c.c. represents one 

 hemolytic dose. It is usually well to prepare a whole series of flasks 

 with various dilutions, and in making a titration to use 1 c.c. of each 



