h 



PRECIPITIN TESTS IN SYPHILIS 457 



positives are obtained 1)}' a routine test. Any attempt to applj' 

 them to weakly positive sera will result in negative results in all 

 except the first tube. 



The accompanying protocol (Table XV) represents the actual 

 results of three quantitative serum Kahn reactions. 



Table XV 



Serum dilu- (U5 (135 (U5 (U5 0/15 (U5 (115 0.15 Titer = 4 x D 



tion in c.c. 

 Serum dilu- None 1:5 1:10 1:20 1:30 1:40 1:50 1:60 



tion 

 Special anti- 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 



gen dil. 

 Serum B + + + - - - - -4x10=40 



Serum B^ + - - - - - - -4x1=4 



Serum L + + + + + + + -4x50 = 200 



Normal serum ________ None 



Saline only 



+ = precipitate. 

 - = no precipitate. 



Serum R was a ease at the beginning of treatment. Serum B^ 

 has received six weeks of treatment. Serum L was identified as 

 a positive control. Normal serum and saline are necessary as 

 negative controls. This is a composite table taken from labora- 

 tory data. The serum controls consisting of serum plus saline are 

 not represented in the diagram. 



Kahn's Verification Test.* — Kahn (1940, 1941) has studied the 

 effect of temperature on the Kahn three tube flocculation test 

 and compared the reactions obtained with normal reagin and 

 syphilitic reagin. He finds that reagin in lower animalsf and 

 nonsyphilitic individuals gives stronger reactions at 1° C. than 

 at 37° C. whereas the reverse is true with syphilitic reagin. The 

 details of his test are given in his papers. 



Description of Kline Test. — Kliiie Microscopic Slide Precipita- 

 tion Test. The Kline test is a microscopic slide precipitation test 

 for the detection of syphilitic reagin. It contains "micro- 

 scopically visible lipid-coated cholesterol plates which clump 

 after being acted upon by positive syphilitic serum or spinal fluid. 

 There is probably a combination of the particle plus the reacting 

 substance and a consequent surface alteration with a lessening of 

 solubility." (Kline, 1931, 1940.) 



*See pp. 434, 43.5 for a discussion of nonspecific reactions. 



tFor a review of literature on normal reagins see paper by Kemp, J. E., 

 Fitzgerald, E. M., and Shepard, M. : Am. J. Syph., Conor, and Ven. Dis. 24: 

 MT, 1940. 



