1 50 IMMUNE SERA 



has shown that the precipitates produced in vitro 

 will, when injected intravenously into animals, pass 

 through the capillaries without harmful effects. 



Pathology of Anaphylactic Shock. Acute ana- 

 phylactic death in guinea-pigs was originally attrib- 

 uted to asphyxia of central origin. Auer and 

 Lewis, 1 however, showed that the asphyxia is due 

 to a tetanic contraction of the bronchial muscle, 

 the contraction being so pronounced that the lumina 

 of the smaller bronchi are occluded, thus preventing 

 both the entrance and the escape of air. In a 

 recent study of the subject, Schultz and Jordan 2 

 show that in guinea-pigs the point of occlusion is 

 usually just beyond the place where the secondary 

 bronchi leave the primary, and in all cases at points 

 commanding large areas of lung tissue. At this 

 point there is the greatest relative (to diameter of 

 lumen) amount of smooth muscle, and there is also 

 normally a thicker mucosa and greater degree of 

 folding of the same relative to the lumen. The 

 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- 



1 Auer and Lewis, Journal Exp. Medicine, Vol. xli, 1910. 



2 Schultz and Jordan, Journal Pharmacol. and Exp. Thera- 

 peutics, Vol. ii, March, 1911. 



