Noguchi's Modification 303 



general paresis, and tabes dorsalis the positive reactions vary. In 

 the former disease some have found as high as 90 per cent, positive; 

 in the latter the usual figures vary about 50 per cent. 



It is thus seen that the occurrence of the reaction is much more 

 conclusive evidence of the presence of syphilitic infection than the 

 failure of the reaction is of its absence. 



Treatment greatly influences the test. When under active treat- 

 ment, either with mercury and iodids or with salvarsan, the reaction 

 of the serums is usually negative. 



Nature of the Reaction. — We now reach the point of considering 

 the nature of the reaction. It does not occur because of the pres- 

 ence in the blood of syphilitics of antibodies which combine with 

 the antigen and fix the complement. It is probably not comple- 

 ment fixation so much as complementary inhibition, through the 

 presence in the blood of syphilitics of certain metabolic products, 

 whose action interferes with the complement in some entirely 

 different manner. 



NOGUCHI'S MODIFICATION OF THE WASSERMANN REACTION 



Noguchi* has modified the Wassermann reaction, first by employ- 

 mg as an antigen an extract of the heart of a normal guinea-pig, 

 and, second, by inaking use of human instead of sheep corpuscles 

 for the hemolytic test. The advantage of the latter depends upon 

 the fact, carefully determined by Noguchi, that human blood-serum 

 contains no amboceptors active in effecting hemolysis of human 

 blood-corpuscles, though it not infrequently contains hemolytic 

 amboceptors for sheep corpuscles. In the directions for making the 

 Wassermann test a control test for determining their presence or 

 absence was found expedient. It will also be remembered that the 

 presence of these amboceptors causes no invalidity of the test, pro- 

 vided it be recognized. 



Noguchi also varies the technic in such a manner that very small 

 quantities of the various reagents are employed — a necessity that 

 arises from the relatively small quantity of the patient's blood ob- 

 tainable according to the method he employs. The reagents 

 are as follows: 



(i) The Serum to be Tested. — To obtain this, Noguchi binds the 

 finger of the patient with a rubber band, makes a good-sized punc- 

 ture near the root of the nail with a Hagedorn needle, and collects 

 about 2 cc. of the blood in a Wright tube (see directions for making 

 the opsonic index). The blood soon coagulates in the tube, which is 

 then scratched with a diamond or file, broken, and the serum re- 

 moved/with a capillary pipet. The serum may or may not be in- 

 activated by heat, according to the option of the experimenter. 

 The dose of the unheated serum is i drop; of the inactivated serum, 



* "Serum Diagnosis of Syphilis," Philadelphia, 1910, J. B. Lippincott Co. 



