ANAPHYLAXIS 177 



it does in rabbits. In fact von Pirquet found that 

 sometimes even after the injection of 200 cc. there 

 was no production of precipitins. Finally it may 

 be remembered that there is no evidence that the 

 precipitin action is other than a test-tube phenom- 

 enon, or that it ever occurs in vivo. Friedemann 

 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 



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



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

 peutics, Vol. ii, March, 1911. 



