370 INFECTION AND RESISTANCE 



Schittenhelm 32 claim that anaphylaxis in dogs is invariably accom- 

 panied by a severe local reaction in the gut. The intestinal mucosa 

 is swollen and contains miliary hemorrhages and the lumen is often 

 filled with a mucus mixed with blood. In the further analysis of the 

 anaphylactic reaction in dogs, Manwaring 33 has recently reported 

 observations of great interest. He investigated the participation in 

 anaphylactic shock of the various organs and determined that shock 

 did not occur when the abdominal vessels were ligated just above 

 the diaphragm. In further localizing the source of shock he found 

 that exclusion of the spleen, stomach, kidneys, suprarenals, and 

 ovaries from the circulation had no effect upon the occurrence of 

 anaphylactic shock. However, when he operated in such a way that 

 the liver was thrown out of circulation, none of the seven dogs that 

 he used reacted with anaphylactic shock to the injection of serum. 

 He concludes from this that the liver is directly responsible in some 

 way for the production of anaphylaxis. The intestines, too, were 

 found, by a similar procedure, to take part, though to a less important 

 extent than the liver. 



Other animals than those mentioned have been little used for 

 anaphylactic experiment. Observations incidental to other work, 

 however, have shown that horses and goats are particularly sensitive. 

 In goats the writer has observed both serum and bacterial anaphy- 

 laxis, and the symptoms here were those of general trembling, weak- 

 ness, labored respiration, and involuntary evacuation of urine. 



The occurrence of anaphylaxis in man will be discussed in a 

 subsequent section. 



The manifestations of "active anaphylaxis," therefore, consist 

 in the profound physiological changes occurring in animals when re- 

 injected after a definite interval with certain substances which, on 

 first injection, were practically harmless. The factors which are of 

 fundamental importance in determining the development of this 

 hypersusceptible or anaphylactic state consist in the nature of the 

 injected substance, the quantity injected, and the interval between 

 administrations. To a great extent, too, the violence of the reaction 

 is dependent upon the path by which the particular substance enters 

 the body. 



Each of these factors, therefore, requires detailed consideration 

 before we can intelligently proceed with a further analysis of the 

 condition. 



The substances with which animals may be sensitized are, in all 

 particulars, identical with the class of substances which we have 

 characterized as "antigens." In fact, up to the present time, 

 there has not been a single authenticated exception to this, and from 

 our present understanding of the mechanism of anaphylaxis we may 



32 Weichhardt and Schittenhelm. Deutsche med. Woch., 19, 1911. 

 33 Manwaring. Zeitschrift f. Immun., Vol. 18, 1911. 



