ANAPHYLAXIS 



6 7 



the offending material. Treatment and prophylaxis take the 

 form of injecting solutions of the responsible protein under 

 the skin. For example ragweed is the most common cause 

 of hay fever. Solutions of its pollen, made in standard dilu- 

 tions of 1-10,000 to 1-500 are injected in rising quantities, 

 beginning with the weakest. Treatment should be given during 

 the winter and spring so that as high a degree of disensiti- 

 zation as possible will be accomplished. Little can be expected 

 in the hay fever season. 



FIG. 19. Illustrating the conception of deviation of complement. 

 Amboceptor; b, antigen; k, complement. (MacNeal.) 



. Complement Fixation. Hemolysis occurs when the serum of a 

 rabbit immunized against washed sheep's red blood cells is mixed 

 with fresh washed sheep's corpuscles in the presence of comple- 

 ment. If, however, complement be absorbed in any way, a solu- 

 tion of the coloring matter of the red cells will not occur in this 

 mixture. Complement will combine with anti-body in the pres- 

 ence of antigen. This fact has been taken advantage of in deter- 

 mining both the nature of antigen and the presence of anti-body. 

 Its most important practical use is in syphilis, to the diagnosis of 

 which Wassermann applied it, and the Wassermann test is for the 

 presence of syphilitic anti-body in the blood serum of syphilitics. 



