372 MARSHALL AND TEAGUE. 



the meningococcus and gonocoecus. Wollstein(38) obtained results contradic- 

 tory to those of VannodCST), but Teague and Torrey(39) were able to confirm 

 Vannbd's work and to show that furthermore differences such as Leuchs had 

 found between typhoid and paratyphoid extracts exist between certain strains 

 of gonocoeci. Kolle and Schatilofi"(40) after having obtained negative results 

 on using complement deflection in the study of experimental recurrent spiro- 

 chetosis in mice and rats, finally obtained serum from a man suffering from the 

 disease and with this were able to differentiate between the different varieties 

 of spirochetal. 



Various attempts have been made to apply the method to the diagnosis of 

 bacterial diseases by testing the serum of the patient against an extract of the 

 bacterium in question. In gonorrhoeal rheumatism positive results were obtained 

 in a fair percentage of cases by Miiller and 0ppenheimer(41), Briick(42) ) and Mea- 

 kins(43). Positive findings were also reported in typhoid and paratyphoid fevers 

 by Leuehs(36). 



Except in its application to the diagnosis of syphilis, where the interpretation 

 of the reaction has already been discussed, the original view of Bordet and 

 Gengou that the method indicates the union of antigen and antibody has been 

 very generally accepted and it is believed by most investigators that it is an 

 antibody sui generis which is concerned here and not the precipitins, agglutinins 

 or bacteriolytic amboceptors. 



PRECIPITIN" TEST. 



The value of the precipitin test has been so thoroughly established by 

 the work of Nuttall, Wassermann, Uhlenhuth and many others, that it 

 is unnecessary to review the literature upon this subject. However, 

 there are a few recent works that may be mentioned briefly. 



Carnwath(45) has of late described a modification, of the technique by which 

 he is enabled to obtain a positive result with very minute amounts of material. 

 The essentials are that the minute blood stain is dissolved in a very small amount 

 of salt solution; that very small glass tubes about 2 millimeters in diameter 

 and 6 millimeters long are employed for the test; that the specific antiserum is 

 introduced by means of a capillary pipette and upon this the suspected fluid is 

 carefully placed in a separate layer. A positive reaction -is shown in a few 

 seconds at the zone of contact of the two fluids as a cloud, which gradually 

 spreads upward. This method is very delicate and enables the observer to 

 secure definite reactions with minute quantities of antiserum and of antigen. 

 Carnwath was also able to apply the Neisser and Sachs method of following 

 the precipitin test with the deflection test with these minute quantities, but he 

 agrees with Uhlenhuth that this is unnecessary. 



Uhlenhuth in 1003 concluded that it is better in forensic cases to employ only 

 such an antiserum as would produce a definite clouding within one or two 

 minutes with a 1: 1000 dilution of the suspected material when there is one 

 part of serum to 20 of the dilution. 



Michaelis and Dehne(46) find that a specific precipitate is dissolved in the 

 presence of an excess of undiluted homologous antigenetic serum. Dehne finds 

 that this is particularly valuable to supplement the test with very minute 

 quantities of antigen ; the homologous serum from the known species being 

 added in case of the positive reaction with the extract of suspected material. 

 He also finds that when a specific antiserum produces clouding with the heterol- 

 ogous serum, the precipitate is dissolved equally well by the addition of homol- 

 ogous or heterologous serum. 



