SUPERSENSITIVENESS OR ANAPHYLAXIS 599 



bacteria treated with their homologous serum, and also by the 

 action of normal serum alone on bacteria and even on coagulated 

 serum. The phenomena of anaphylaxis therefore constitute an 

 accident, as it were, in the process of immunisation, which is to 

 be regarded as a reaction of the living organism against the 

 introduction of foreign proteins. In this way there is also 

 explained the marked fall in complement in anaphylactic shock, 

 which has been found to occur by Friedberger, Scott, and others. 

 Friedberger holds that though the various anaphylatoxins are 

 similar, or, at least, closely allied substances, there is nothing 

 specific in their nature ; what is specific is merely the union 

 of antigen and anti-substance, the combination when acted upon 

 by complement giving rise to the poisonous substance. 



Besredka considers that the sensitising and the toxic factors in the 

 horse serum are not one and the same. He finds that serum heated to a 

 certain temperature may still have the power of inducing the condition of 

 anaphylaxis, but has lost the power of bringing about the toxic phenomena . 

 when injected into an anaphylactic animal. This result has, however, 

 been explained. by others as being due to the fact that the sensitising dose 

 is so much smaller than the toxic dose (vide supra) on re-injection ; 

 accordingly the effect of heat may be to reduce the latter below the fatal 

 limit without having a corresponding effect on the sensitising dose. On 

 the other hand, Gay and Southard do not believe in the theory of a re- 

 action body. They consider that the condition depends on the presence 

 of a substance in the serum which they call anaphylactin, and which 

 persists in the blood of the guinea-pig for a long period of time. This acts 

 as a slight irritant to the nerve-cells, and produces in them an increased 

 affinity for certain molecules in the serum. Accordingly, when the 

 second injection is made, the rapid combination of these molecules with 

 the cells results in the disturbances described. This view has, however, 

 received little support, and there are various facts against it, especially 

 in relation to the transference of anaphylaxis. 



It is still an open question as to what extent the phenomena 

 of anaphylaxis just described are of the same nature as the 

 supersensitiveness or allergy manifested by patients suffering from 

 disease to the products of the corresponding organism, e.g., to 

 tuberculin, mallein, etc. (pp. 290, 316); though in all probability 

 they are at least similar in essence. It was held for some time as 

 a distinction that this supersensitiveness in infections to bacterial 

 products could not be transferred to another animal, but recent 

 observations show that in certain circumstances this is possible 

 in the case of tuberculin. According to some observers, the 

 phenomena of supersensitiveness of tubercular patients to tuber- 

 culin is due to the combination of the injected antigen with 

 molecules of anti-substance resident in the tissue cells, the so- 

 called " sessile receptors " ; but, according to Friedberger, the 



