THE MANUFACTURE OF ANTISERA 753 



SUBSTANCES USED FOR DIAGNOSTIC TESTS 



LUETIN. Noguchi* has developed a preparation known as luetin 

 which is used in the diagnosis of syphilis. The material is prepared 

 from a number of strains of Spirochata pallida grown, under anaerobic 

 conditions, on special ascites agar and bouillon media. After abundant 

 growth of the spirochetes occurs, the agar cultures are ground and mixed 

 into a paste. To this material fluid cultures are added in sufficient 

 proportion to form a liquid emulsion. The organisms are then killed 

 by heating at 60 for one hour and a preservative is added. 



In applying this diagnostic material to a suspected syphilitic case 

 0.05 c.c. is very carefully injected into, not beneath, the skin. An area 

 on the anterp-internal surface of the upper arm is usually chosen as the 

 s.ite of injection. A positive diagnosis of syphilis is indicated if, after 

 the third day a marked cutaneous eruption appears at the point of 

 inoculation. 



ANTIGENS. Certain antigens, such as gonococcus and syphilitic 

 antigen, are of value for the purpose of conducting complement fixation 

 tests in laboratory diagnosis. Gonococcus antigen consists of an ex- 

 tract or filtrate prepared from a suspension of polyvalent gonococci. 

 Syphilitic antigen consists of an extract prepared from either luetic 

 or certain normal tissues such as beef or human heart muscle. Tuber- 

 culosis antigen, as described by Craig, f consists of the filtrates of 

 specially prepared cultures of Bact. tuberculosis. 



THE ScmcK TEST. The susceptibility or non-susceptibility of 

 individuals to diphtheria may be determined by the application of the 

 test described by Schick.J For this purpose standardized diphtheria 

 toxin is required. 0.1-^0.2 c.c. of a relatively fresh normal saline solu- 

 tion containing J^o minimum lethal dose of diphtheria toxin, for a 

 25o-g. guinea-pig, is injected intracutaneously. The appearance of a 

 circumscribed area of redness at the site of injection after twenty-four 

 to forty-eight hours indicates that the individual possesses practically 

 no immunity against diphtheria. 



* Noguchi, H. : Jour. Exp. Med., xiv, Vol. 16. 

 t Craig, Am. Jour. Med. Sci., 1915. ISO, p. 781. 

 t Schick, Munch. Med. Woch. 1913, 60, p. 2608. 



