318 IMMUNOLOGICAL METHODS OF DIAGNOSIS 



of having first prepared an antigen with which a specific syphilitic 

 reaction may be obtained in a large percentage of infected individuals. 



Preparation of the Antigen. Pure placental ascites agar cultures 

 of the pallida are ground up in a mortar with placental ascites 

 bouillon cultures of the organisms until a fairly thin emulsion is 

 obtained. This is sterilized for one hour at 60 C. and treated with 

 tricresol to the extent of 0.5 per cent. The resultant product Noguchi 

 has termed luetin. After being tested for its sterility it is ready 

 for use. A similar preparation is made from sterile culture material 

 and constitutes the control fluid. 



Injection of the Patient. Before using, the contents of the luetin 

 bottle, which must be kept in the ice-box and frequently examined 

 for its sterility, should be thoroughly shaken, so as to bring about 

 an even suspension of the spirochetes. With a sterile pipette equal 

 parts of the luetin and sterile saline are then placed in a tuberculin 

 syringe and 0.07 c.c. injected in the case of an adult and 0.05 c.c. 

 in infants. The injections are made intracutaneously , the left arm 

 being chosen for the luetin and the right arm for the control fluid, 

 of which a corresponding amount, likewise diluted with saline, is 

 used. Separate syringes are kept for the luetin and the control 

 fluid. Noguchi, moreover, advises that each arm be injected at 

 two points, about 5 cm. apart. Considering the severity of some of 

 the reactions, however, I should personally advise single injections. 



Reactions. While in non-syphilitic individuals the effect of the 

 luetin and the control injection is identical and merely represents 

 a slight traumatic reaction, which recedes within forty-eight hours 

 and leaves no induration, there may be a marked difference between 

 the two sides in syphilitic persons. Noguchi here distinguishes three 

 types of reaction at the points where the luetin has been injected. 

 In the first or papular form "a large, raised, reddish, indurated 

 papule, usually from 5 to 10 mm. in diameter, makes its appearance 

 in twenty-four to forty-eight hours. The papule may be surrounded 

 by a diffuse zone of redness and show marked telangiectasis. The 

 dimensions and the degree of induration slowly increase during the 

 following three or four days, after which the inflammatory processes 

 begin to recede. The color of the papule gradually becomes dark 

 bluish red. The induration disappears within one week, except in 

 certain instances, in which a trace of the reaction may persist for a 

 longer period. This latter effect is usually seen among patients with 



