430 The Philippine Journal of Science 1923 



of cases and, preferably, strongly positive. Another disadvan- 

 tage is the confusion which arises in excluding, in positive cases, 

 possible associated infection with syphilis and, in many tropical 

 countries, with yaws. It would be impracticable to resort to 

 the therapeutic test to eliminate the possibility of these diseases 

 in interpreting the reaction. 



Interesting and important as the fact is, from an immuno- 

 logical standpoint, that sera of lepers become negative under 

 treatment directed against the specific infection and do not yield 

 to antisyphilitic drugs, it seemed useless to attempt an elabora- 

 tion of the Wassermann reaction in the hope of utilizing it as 

 ft measure of the response of lepers to treatment. Consequently, 

 investigation was made of the availability of other antigens for 

 this purpose, namely, bacterial 



COMPLEMENT FIXATION WITH BACTERIAL ANTIGEN 



Although extracts of various tissues, leprous and nonleprous, 

 as antigens have in the hands of previous investigators given 

 somewhat higher percentages of positive results than lipoidal 

 antigens, as used in the Wassermann test, no investigation was 

 made of these substances in view of the more-promising results 

 reported from the use of bacterial suspensions, especially of 

 Bacillus tuberculosis (human). 



It is not surprising that complement fixation occurs with 

 leprous serum in a certain proportion of cases in the presence 

 of antigens of various acid-fast and even certain non-acid-fast 

 organisms, in view of the experimentally demonstrated cross 

 fixations with the sera of animals immune to a single species 

 of the acid-fast group and antigen from various related bac- 

 teria. The subject of cross fixations with serum of animals 

 immunized to acid-fast organisms has been investigated by Gen- 

 gou,(3) Much and Leschke,(7) Claypole,U) and others, and there 

 has been a small number of investigations in which various bac- 

 terial antigens, especially of the acid-fast group, have been used 

 in complement-fixation tests with leprous serum. These have 

 been tabulated and discussed by Cooke who has added his own 

 observations. The result of these studies has shown that 

 bacillary suspensions are better antigens in complement-fixation 

 tests with leprosy than lipoidal antigens or tissue extracts. In 

 Cooke's series of experiments with sera from twenty cases of 

 leprosy, in which antigens prepared from suspensions of 

 eighteen different organisms, for the most part of the acid-fast 

 group, were used, that of Bacillus tuberculosis (human) gave the 



