190 APPLIED IMMUNOLOGY 



large inoculations of dead gonococci do not produce 

 the reaction in non-gonorrhoeal subjects. The test 

 finds its greatest field of usefulness in the differential 

 diagnosis of obscure synovial, joint, periosteal and 

 gjTisecological affections ; also promises to be of value 

 in the control of candidates for matrimony and as a 

 guide to the insufficiency of treatment. 



Cutaneous Reaction of Typhoid Immunity, — Gay 

 and Force very recently have announced a decisive 

 skin reaction in 95 per cent, of persons who have had 

 typhoid fever. Furthermore, they found that nine 

 out of fifteen individuals inoculated from four and 

 three-fourths years to eight months previously, in ac- 

 cordance with the method of the United States Army, 

 gave positive reactions, and that of twenty-five per- 

 sons inoculated within eight months, none showed a 

 negative response. They conclude that the test may 

 serve as an index of the duration of typhoid immunity 

 following protective inoculation, thereby governing 

 the time for re-inoculation. 



The preparation used for the test consists of ty- 

 phoid cultures grown for five days in five per cent, 

 glycerin-broth. This is evaporated to one-tenth of its 

 original volume over acetone, simulating the prepara- 

 tion of Koch's old tuberculin. The test is carried out 

 precisely as is von Pirquet's tuberculin method, pro- 

 ducing reactions of identical character (see page 180) • 



