WASSERMANN EEACTION 129 



of the extract alone and of the serum alone can be tested at the 

 same time. 



Quantitative Method. — Three tubes with different doses of 

 complement will be sufficient for routine examination. 



To each of these add '025 o. c. of the serum to be tested (heated at 55° C. ) 

 and 0'3 c.e. of diluted antigen {vide infra). 



Add to the three tubes respectively, i, 7, and 10 doses of complement 

 (the dose being that for - 5 c.c. of sensitised corpuscles), and make up the 

 amount with 0'8 per cent, saline to - 5 c.c. 



Place the tubes in the incubator for an hour at 37° C. 



Then add to each 0'5 c.c. of suspension of sensitised ox corpuscles, and 

 place again in the incubator for another hour. Place the tubes aside at 

 the room temperature till the nori-lysed corpuscles have sedimented — con- 

 veniently till next morning — and then read the results. 



Controls should be made in each test as follows : one tube containing 

 the stated amount of antigen along with 2 doses of complement and 

 one containing the stated amount of heated serum alone with two 

 doses of complement; to all these 0'5 c.e. of sensitised corpuscles is 

 added after incubation for an hour. It is also advisable to put up 'a series 

 with a known syphilitic serum — in routine work it is convenient to keep 

 one from the last day's tests. 



Antigen. — Various antigens have been used, but we have found that 

 the following gives very satisfactory results : — 



Take the muscle of a human heart and free it from fat ; then mince it 

 finely. Add by weight three parts of alcohol to one part of minced muscle. 

 Allow the mixture to stand for a week or longer, shaking it up from time 

 to time ; then filter through filter-paper. For use it is to be diluted with 

 0'8 per cent, sodium chloride solution, usually in the proportion of one 

 part of extract and eight parts of saline — diluted antigen. (It is an advan- 

 tage in the case of each specimen of extract to test various dilutions of it 

 with a known syphilitic serum and find the dilution which gives most de- 

 viation, and then to use this dilution in subsequent tests.) In diluting 

 the extract for any test, the necessary amount of saline should be put in 

 a test-tube and the extract run in on the top of it, the test-tube being 

 rotated meanwhile so as to mix slowly. In this way the maximum tur- 

 bidity is obtained, and this is associated with marked deviating effect. 



With the amounts of extract and serum mentioned, a positive 

 result indicating the presence of syphilis may be definitely ac- 

 cepted when five or more doses of complement are deviated in 

 addition to the amount fixed in the controls, whereas the devia- 

 tion of three doses is highly suspicious, and by some observers 

 is accepted as a positive result. The interpretation must vary 

 somewhat according to circumstances ; for example, when a 

 syphilitic patient is being treated the deviation of three doses 

 would still be accepted as positive. Some observers use the 

 same amount of complement in each tube, but vary the amounts 

 of suspected serum, and in this way some idea of the deviating 

 power of the serum is obtained, but we consider that the method 

 given is to be preferred. 



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