844 Serum Disease. 



ing to the formation of toxic products (artificial anaphylaxis of Detre). 

 The natural hypersensibility shows considerable individual variations 

 as regards the quantity and derivation of heterogenous proteid. Some 

 anaphylactic animals are made ill only by considerable quantities of 

 an alien proteid, while others react with severe symptoms of disease, 

 even to small amounts of alien proteid (blood serum). The symp- 

 toms occur in all cases of natural anaphylaxis either immediately or 

 soon after the ingestion of the respective proteids. 



Artificial anaphylaxis, on the other hand, only develops subse- 

 quently to the introduction of certain proteid substances. It may 

 indeed happen that the organism, being under the influence of some 

 proteid (usually infectious substances) becomes intolerant to other 

 heterogenous proteids just as in natural anaphylaxis; but usually, and 

 in a typical manner, the hypersensibility develops after the animal has 

 been treated with blood serum (serum anaphylaxis) or other heter- 

 ogenous albumins. After a single injection under such circumstances 

 the symptoms may occur only after 8 to 14 days (normal serum disease), 

 after a sufficient amount of antibodies with the power of dissociating 

 proteids have formed in the organism which was not originally hyper- 

 sensitive, and these then cause a rapid disintegration of the heter- 

 ogenous proteid substances which are still circulating in the blood. 

 On the other hand, even very small amounts of serum will give rise to 

 these symptoms only after one or several reinjections and then only in 

 a portion of the animals. The symptoms either follow immediately 

 (immediate reaction or serum disease) in cases in which the second 

 injection was made after about 10 days, or only after 1 to 3 to 6 days 

 if the interval was longer (hastened reaction). In the last two cases 

 the anaphylaxis is strictly specific and occurs only in response to those 

 substances with which the animal had been treated previously; it may 

 also be transmitted passivel.v to other animals, or by pregnant animals 

 to the young (passive hypersensibility). Animals usually become an- 

 aphylactic primarily and exclusively in response to heterogenous 

 proteids, but occasionally a homogenous proteid may give rise to serum 

 disease as was shown by the observations of Lorenz and Bartels. In a 

 case of the authors a healthy horse acquired serum disease after having 

 been vaccinated with the serum of a healthy horse. 



It may here be mentioiied by the way, that it has been possible to render 

 experimental animals anaphylactic (Rosenan, Anderson) by feeding lilood serum 

 or meat from healthy horses. This fact opens the way for an explanation of those 

 cases of urticaria which occur occasionally after the ingestion of certain food 

 stuffs. 



The serum disease is only one form of anaphylaxis which includes among 

 others the allergy of tuberculous or glanderous animals to tuberculin or mallein 

 (see Vol. I). 



Symptoms. The symptoms occur in domestic animals usually as 

 soon as 5 to 30 minutes to 3 hours after a first serum injection; only 

 Kovarzik saw the occurrence of serum disease delayed until after the 

 second injection which was administered seven days after the first. 

 In horses there may be only a nettlerash with severe pruritus, which 

 may involve the entire body (Bartels), or edematous swellings form, 

 either alone or in association with the urticaria, affecting especially the 

 head and the point of injection (Zinner). In cattle the most striking 

 phenomena consist in a generalized urticaria associated with severe 

 pruritus, and in edematous swellings which are sometimes severe and 

 affect principally the head and the perineum. In addition one may 

 observe great restlessness, pain at tlie point of injection, salivation, 



