PRACTICAL APPLICATIONS OF METHOD 205 



cently suggested the importance of specific lipase production as a 

 cause of hemolysis, suggests that the Wassermann reaction is due to 

 fixation exerted by the products of the action of a specific lipase 

 formed in the syphilitic body against "lues-lipoids." This theory is 

 open to objections similar to those mentioned above, namely, that 

 the antigen need not necessarily be a lues-lipoid, but may be derived 

 from normal organs. Other theories have been brought forward by 

 Bruck, Weil, Braun, Manwaring, and more recently by Rabino- 

 witch. 28 The data supporting most of these theories are, as yet, too 

 speculative to justify our discussion of them at any length. The 

 only fact which seems established with any reasonable certainty is 

 the independence of the Wassermann test from a specific antigen- 

 antibody reaction in the usual sense. 



Although the Wassermann reaction is thus apparently not based 

 on those principles in the investigation of which it was discovered, 

 its practical diagnostic value is not therefore diminished. . For its 

 proper performance any of the methods of antigen preparation con- 

 sidered above may be employed, provided that the usefulness of the 

 preparation utilized is carefully controlled in each case as indicated. 

 Since, of course, a hemolytic system is used in such tests as an in- 

 dicator, it is necessary also to titrate sensitizer and alexin. 



From what has been said in another place concerning the quanti- 

 tative relations of alexin and amboceptor or sensitizer (see reference 

 to work of Morgenroth and Sachs, p. 163), it is evident that the use 

 of too strongly sensitized cells might result in hemolysis, if a slight 

 fraction of alexin were left unbound by a weak syphilis reaction. 

 Conversely the use of too large a quantity of alexin would result in 

 hemolysis, since, even if the amount of syphilitic fixation were con- 

 siderable, a sufficient excess of alexin might remain. The use of 

 uniform amounts of fresh guinea pig serum in each case does not 

 control this adequately, for different specimens of guinea pig serum 

 may vary considerably in alexin content. In consequence, titra- 

 tions of both sensitizer and alexin should be made. For practical 

 purposes it is quite enough to titrate the hemolytic sensitizer every 

 few weeks and use a stated amount in successive reactions. The 

 alexin or complement can then be titrated individually for each set 

 of reactions. Examples of such preliminary titrations follow: 



Titration of Hemolytic Amboceptor or Sensitizer 



Rabbit injected 3 times at 5-day intervals with washed sheep 

 corpuscles . . . . , 3, 4, and 5 c. c., and bled 10 days after the last 

 injection. 29 



28 Rabinowitch. Centralbl. f. Bakt., Orig., 1914. 



29 In immunizing 1 animals with blood cells for this or any other purpose 

 it is necessary to wash the cells very carefully in salt solution. Unless this is 



