SERUM SICKNESS 143 



phylaxis " for the phenomenon. Their experiments 

 indicate that the theory advanced by v. Pirquet and 

 Schick is untenable, and they conclude that " the 

 horse serum contains a substance, anaphylactin, 

 which is not absorbed by the guinea pig tissue, is 

 not neutralized, and is eliminated from the animal 

 body with great slowness. When a normal guinea 

 pig is injected with a small amount of horse serum, 

 the greater part of its elements are rapidly elimin- 

 ated ; the anaphylactin, however, remains and acts 

 as a constant irritant to the body cells, so that their 

 avidity for the other assimilable elements of horse 

 serum which have accompanied the anaphylactin, 

 becomes enormously increased. At the end of two 

 weeks of constant stimulation on the part of the 

 anaphylactin, and of constantly increasing avidity 

 on the part of the somatic cells, a condition has 

 arrived when the cells, if suddenly presented with 

 a large amount of horse serum, are overwhelmed 

 in the exercise of their assimilating functions, and 

 functional equilibrium is so disturbed that local 

 or general death may follow." The intoxication 

 caused by the second injection depends upon con- 

 stituents of the serum eliminable by the animal 

 body. 



According to Gay and Southard the tissue of 

 the guinea pig examined during the anaphylactic 

 phase showed no characteristic lesions. Striking mul- 

 tiple haemorrhages accompany the toxic phase. The 



