77//; .1 \1 /'//!/,. I C"/7C' .WTIIiOhV i A \ A I'll YLACTIX) 203 



clays after the sensitizing injection, increases to a maximum between 

 the 15th. and 30th days, and then very slowly decreases. The reaction 

 of antibody and antigen is strictly quantitative, as with all ambo- 

 ceptor reactions. Tlie amount of antibody developed seems to be 

 limited, for after a sensitized animal is given a sub-lethal intoxicating 

 dose of protein it may be no longer sensitive to this protein, and this 

 refractory or anti-anaphylactic condition persists for three weeks or 

 more. It has been demonstrated, especially conclusively by Weil and 

 Coca,^^ that this refractory condition is, as Friedberger suggested, de- 

 pendent upon saturation or exhaustion of all the anaphylactic anti- 

 bodies, and hence the amount of these antibodies present free in the 

 blood of a sensitized animal must be relatively small, for a few milli- 

 grams of the specific protein is sufficient to saturate them, e. g., the 

 amount of antibody present in 3 c.c. of serum from a guinea-pig sen- 

 sitized with horse serum could be neutralized with from 0.0005 to 

 0.01 c.c. of horse serum. ^^ They are, however, very persistent, remain- 

 nig in guinea-pigs through the entire life of an animal sensitized 

 when young. They also pass from the mother to the fetus, conferring 

 a passive sensitization which, like passive sensitization from injec- 

 tion of serum from a sensitized animal, is of relatively brief duration, 

 in contrast to the persistence of active sensitization. ^^'^ Anaphylactin, 

 like amboceptor, resists heating at 56° for one hour, and is salted out 

 from serum in the globulin fraction.^^'^ ■ Friedberger contends that it 

 is identical with the precipitin, a view yet under discussion,'* but 

 strongly supported by Weil 's observations.^*^ 



Weil ^■' has observed certain phenomena which led him to conclude 

 that in anaphylaxis the specific antibody must be largely fixed in the 

 cells, and that it is in the cells that the reaction occurs; the anti- 

 bodies present in the blood of the sensitized animal are insufficient to 

 protect its cells from the foreign protein, hence the cellular intoxica- 

 tion. In support of this idea is the observation of Dale ^*' that the 

 isolated smooth muscle of sensitized guinea-pigs is specifically sensitive 

 to the foreign protein. Weil states that ' ' all the evidence proves con- 



32Zeit. Immiinit-it, 1013 (17), 141. 



33 Anderson and Frost, Jour. Med. Res., 1010 (23), 31. 



33a The brief duration of passive sensitization presumably dejiends on the forma- 

 tion of antibodies for the foreign sensitizing serum, constitutintr tlie condition of 

 "antiscnsitization" as contrasted with the refractory period wliich results from 

 the exliaustion of antil)odies by antigen. (See Weil, Zeit. Immunitiit., 1013 (20), 

 199; 1014 (23), 1.) 



3_3b However, Scliiff and ]Moore state that in immune sera the allKunin fraction 

 contains both the agent that confers passive sensitization and llic constituent 

 that causes the "primary toxicity" of foreign sera. (Zeit. Immunitiit.. 1014 (22), 

 CIO.) 



34 See Zinsser, Jour. Exp. Med.. 1012 (15), 529. 

 '34a Jour. Immunol.. 1916 (1), 1. 



35Jour. Med. Research, 1913 (27), 407: 1014 (30). 200-364: 1015 (321, 107. 

 3G Jour. Pharm.. 1013 (4), 167. 



