i6 3 



that it could no longer be used for the cutaneous reaction. They named 

 this antibody "antikutine," and proved its existence as follows: 



Twenty days after the last tuberculin injection the serum of the patient 

 is withdrawn and mixed with tuberculin in i, 2, 5 and 10 per cent, tuber- 

 culin serum mixtures. These are kept in the incubator for two hours, then 

 in the ice-box for twenty hours and then used for the cutaneous reaction. 

 The abrasions made with the v. Pirquet borer must be at least 3 cm. dis- 

 tant from each other, intervened by control spots. By gently stretching 

 the skin of the forearm one can apply ten reactions over this area. Only a 

 distinct papule formation should count as a positive reaction and ob- 

 servation should be continued for six days. Just as antituberculin 

 amboceptors may be found in the serum of patients who have not had 

 any specific treatment, so also can these antikutine bodies originate 

 spontaneously. 



Marmorek described still another antibody, found in a horse immunized 

 with living young tubercle bacilli. This serum when mixed with the urine 

 from patients with active febrile tuberculosis will fix complement. Exam- 

 inations by Citron and Klinkert showed that here one is probably dealing 

 with an antibody brought about by immunization against altered tuber- 

 culous tissue. 



In former times a negative tuberculin reaction after a prolonged treat- 

 ment was stamped as a cure of the tuberculosis, a fact obviously incorrect; 

 for no matter how successful the tuberculin therapy may be, it cannot 

 always be considered as a complete curative procedure. In general, that 

 method should be adopted which makes the individual non-susceptible to 

 the largest doses of tuberculin. It was found in practice that those patients 

 having the greatest amount of antituberculin in their serum usually 

 offered a better prognosis. 



The experiences gained by the employment of the complement 



Serum fixation test in tuberculosis lead to its application in the study 



Diagnosis of of syphilis. The difficulties in this disease were greater, inas- 



Syphilis. much as there were no bacteria or preparations like tuberculin 



which could be used as antigen. 



Syphilitic human organ extracts were employed, with the idea that these would 

 contain the specific virus. The serum of monkeys previously immunized with such 

 extracts, when mixed in vitro with the latter, gave complement fixation. ' This experi- 

 ment is not, however, conclusive; the positive reaction may be due to anti-human 

 proteid amboceptors produced at the same time by the injection of the human serum 

 contained in the organ extract. The experiment was changed and the syphilitic organ 

 extracts from apes were used so as to exclude this error. Even in this way complement 

 fixation was attained. Later on it was found unnecessary to inject the monkeys with 

 the extracts since after ordinary infection their serum would give complement fixation. 

 In this manner it was almost definitely established firstly, that these extracts contained 



