178 IMMUNE SERA 



fatal asphyxia observed in guinea-pigs is therefore 

 due to the peculiar anatomical condition of the 

 bronchial tree in these animals. In white mice 

 the anaphylactic reaction shows itself by increased 

 peristalsis, contractions of the bladder, increased 

 irritability of the skin, etc. The respiratory symp- 

 toms are absent. This is clearly because the mucosa 

 of the bronchial tree is nowhere sufficiently thick 

 or folded, relative to the amount of muscle and to 

 the diameter of lumen, to produce occlusion under the 

 amount of constriction produced by the contracting 

 musculature. The recent work of Schultz shows 

 that serum anaphylaxis is essentially a hyper- 

 sensitization of smooth muscle generally. 



It is possible that the occasional occurrence of 

 severe symptoms and even of death in man follow- 

 ing the injection of serum is sometimes due to an 

 abnormal development or condition of the mucous 

 membrane and smooth muscle of the bronchi. 

 Some support is given to this view by the more 

 frequent occurrence of these disturbances in asth- 

 matic individuals. 



Relation of Anaphylaxis to Serum Therapy. 

 Returning now to the relation of the experimental 

 work in anaphylaxis to serum therapy, attention 

 should be called to the work of Steinhardt and Banz- 

 haf, who show that the anaphylactic reaction in 

 rabbits differs considerably in character from that 

 observed in guinea-pigs. These authors, therefore, 



