210 PUBLIC HEALTH BACTERIOLOGY 



is likely, always excluding treatment with mercury, which 

 inhibits the reaction. 



If, at any stage, the patient is under treatment with 

 mercury, a negative reaction has no value for diagnosis. 

 Stop treatment for one to two months, and test again. 

 Salvarsan or " 606 " also inhibits the test. 



In a few cases of syphilis, no reaction is given at any 

 time. 



In congenital syphilis, the reaction may persist through- 

 out life, and be present even where there are no evidences 

 of active pathological processes. The examination of 

 the blood of the mother will usually give corroboration, 

 and that of the father may, but not necessarily. 



In tabes dorsalis, general paralysis, and aneurysm, a 

 large number of positive results have been obtained ; about 

 60 per cent in tabes, and 99 per cent in general paralysis. 

 In the latter it is got in the cerebrospinal fluid. 



Porges-Meier Reaction. Equal parts of clear blood 

 serum and a I per cent emulsion of lecithin or other lipoid 

 substance in carbolized salt solution, are mixed and allowed 

 to stand at room temperature for 5 hours. Normal serum 

 causes no precipitate, but syphilitic serum does. This test 

 is not nearly so delicate macroscopically as Wassermann's, 

 and hence, while much more simple, is not so readily 

 interpreted by the naked eye. Jacobsthal has studied it 

 microscopically, by the aid of the ultra-microscope. He 

 found that with normal serum, the particles of the lecithin 

 emulsion appeared as isolated brilliant points, showing 

 active Brownian movements. With a syphilitic serum, 

 these brilliant points were seen to run together to form a 

 large and brilliant mass. Intermediate reactions were 

 noted, in which partial agglomeration occurred into small 

 brilliant masses or brilliant chains. These phenomena 

 were tested against the Wassermann reaction, and were 

 found to run parallel to it. 



Determination of an Antigen by Complement- 

 Fixation. The same principles apply, but in this case 

 the immune-body present in the serum is known, and a 

 serum is tested which is supposed to contain the corres- 

 ponding antigen It has been applied to test blood for 



