PRACTICAL APPLICATIONS OF METHOD 217 



gonococci, has been employed by many observers during recent years, 

 and promises to be of great value. 



Here, too, the production of the antigen is the only feature of 

 the reaction which has offered difficulties. Since the researches of 

 Torrey have shown that not all races of gonococcus are antigenically 

 alike, it seems necessary to produce a polyvalent antigen. At the 

 Xew York Department of Health at present the antigen is prepared 

 by using the ten Torrey strains. Stock cultures are carried on neu- 

 tral veal agar and cultures are planted upon salt-free veal agar. 

 Twenty-four-hour growths, washed off in neutral distilled water, are 

 kept in a water bath at 56 C. for two hours, and then filtered 

 through, first, a Buchner and then a Berkefeld filter. They are then 

 sterilized for one hour. 



COMPLEMENT FIXATION IN TUBEBCTJLOSIS 



Attempts to apply complement fixation to the diagnosis of tuber- 

 culosis have been made by as many as thirty or more investigators 

 with varying results. Wassermann and his collaborators attempted 

 it before they succeeded in developing the Wassermann reaction in 

 syphilis. Recently, intensive work has been done on the subject by 

 Besredka, 44 Petroff, 45 Craig, 46 Bronfenbrenner, 47 and Miller and 

 Zinsser. 48 Results have warranted the application of the reaction to 

 clinical tuberculosis, although the actual degree of usefulness of the 

 reaction must still await the multiplication of cases tested. The diffi- 

 culty has of course consisted in the development of a suitable antigen. 

 The antigen of Petroff has consisted of a filtrate of potato broth. 

 Besredka has used a filtrate of cultures made upon egg broth. Craig 

 has used Besredka's antigen and suspensions of ground bacilli, Mil- 

 ler and Zinsser 48 have employed an antigen made by triturating liv- 

 ing and dead bacilli with crystals of table salt, then adding distilled 

 water to isotonicity. With all of the antigens favorable results have 

 been obtained. Our own results seem to check up with clinical 

 diagnoses in over 80 per cent, of the cases and so far have appeared 

 to give practically no positive results in negative cases and indicated 

 only active tuberculosis and not healed lesions. 



The reactions are carried out by methods entirely analogous to 

 those employed in the Wassermann reaction, but careful antigen 

 titrations must be done. 



44 Besredka. Ztschr. f. Immunit., 1914. 



4r > Petroff. 



46 Craijr. Am. Jour. Med. Sc., Dec.. 1015, p. 781. 



17 Broiifenbrenner : Arch. Int. Med., 1914, No. 6, 78G. Ztschr. f. Immunit., 

 1914, XXIII, 2, 21. 



48 Miller & Zinsser : Proc. Soc. Exper. Biol. and Med., 1916, 134. Jour. 

 Lab. and Clinical Med., Vol. I. p. 817. 



