11 YPEK.SENSITIVENESS 487 



passively. Those who hold to the plurality of antibodies for any 

 one antigen have offered certain evidence against tlie assumption 

 that precipitin and sensitizing antibody are the same. They point 

 out that Longcope (1913), Spain and Grove (1925) and others 

 were unable to sensitize guinea pigs with precipitating serum ob- 

 tained from rats. This may be due to species differences as pointed 

 out elsewhere in this chapter. Zinsser remarks that perhaps the 

 low titer of precipitins in immune rat serum may be a factor. 

 Furthermore, he does not regard certain quantitative discrepancies 

 observed between the precipitating and sensitizing power of a 

 serum, as significant since the formation of a visible precipitate 

 depends not only upon the union of antigen and antibody but 

 also upon many additional factors which have been discussed in 

 preceding chapters. In fact one makes use of the failure of 

 antigen-antibody mixtures to develop precipitates when he em- 

 ploys the "suppression phenomenon" of Landsteiner in the study 

 of specificity. Opie (1924) in his study of the Arthus phenomenon 

 noted definite correlation between the sensitizing and precipitat- 

 ing property of immune serum. According to Zinsser (1931), 

 Ward and Enders carried out studies in his laboratory which 

 indicate that the complement fixing titer of a serum is a more 

 accurate measure of its sensitizing property than the precipitin 

 titer. Since we accept as a working hypothesis for the present 

 the unitarian concept of antibodies, it is obvious that we regard 

 precipitin and anaphylactic antibody as the same. 



Specificity of the Reaction. — The specificity of the reaction has 

 been investigated extensively by Wells and also by Dale and 

 others. They liave found the reaction to be not only very specific 

 Init far more delicate than any biochemical tests known. 



The Changes in Metabolism During- Shock. — Wells (1929) in 

 an excellent condensed discussion of anaphylaxis reviews the 

 literature on the pathological, physiological and metabolic changes 

 in anaphylactic shock. Major (1914) reports an increase in non- 

 coagulable nitrogen, creatinine and urea in the blood; Abder- 

 halden and Wertheimer note a decrease in the gas metabolism 

 as a whole; Eggstein and others describe a marked acidosis asso- 

 ciated with the asphyxia in guinea pigs, while McCullough and 

 O'Neill report a marked increase in lactic acid. Among other 



