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Scientific Proceedings (75). 



up; the other was a patient with tuberculous peritonitis who had 

 had lues. 



Almost all the healed cases had positive skin tests, yet 54 of 

 the total series of 88 showed negative fixation; 24 of the 103 cases 

 in which tuberculosis had been excluded gave marked intradermic 

 reaction to tuberculin. The fixation test was negative in these 

 24 also. 



In the foregoing communication, we have reported an antigen 

 for complement-fixation in tuberculosis which has seemed to give 

 us results more regular and satisfactory than those reported by 

 other workers and which has the advantages of great simplicity. 

 The nature of the reaction and its results incline us to believe 

 that we are dealing with a specific reaction which depends 

 upon the presence or absence of antibodies to the tubercle bacillus 

 in the circulation of the patient. It is well to bear this in 

 mind in judging the results of the reaction, since it must not be 

 forgotten that specific complement fixation may not be a direct 

 measure of infection, but rather indirectly it may point to the 

 invasion of the body by a specific microorganism, by determining 

 the presence of antibodies. Thus, it may be too much to expect, 

 especially in a disease so chronic as tuberculosis, to find antibodies 

 circulating in all forms and in all stages of the disease. Perhaps 

 this will make it more easy to understand why the reaction has 

 given positive results in active cases only, nearly always negative 

 ones in inactive tuberculosis, and was occasionally negative when 

 tubercle bacilli were in the sputum but the clinical condition was 

 one of arrested disease. It is this aspect of the reaction particularly 

 which leads us to hope that it will be of clinical value in indicating, 

 not so much the existence of infection as of determining the activity 

 of the focus, and, incidentally, giving us a method of studying the 

 fluctuations of antibodies during the disease. The work will, of 

 course, have to be continued by multiplying the number of cases 

 already observed. We are also proceeding in our own laboratory 

 to study the specificity of antigens made with bovine cultures and 

 to study the relationship of this reaction to the diagnostic tuber- 

 culin tests. 



