974 ANAPHYLAXIS AND ANAPHYLACTOID REACTIONS 



salivation and lacrymation (see Gahringer),' In man, the respiratory difficulty may be 

 prominent, but as a rule the circulatory difficulty is more severe and the cause of death. 

 Edema may be observed in lower animals, but is usually demonstrated only by microscopic 

 examination; subcutaneous and pulmonary edema may be severe in man. 



The anatomical findings vary with the acuteness and severity of the shock and with the 

 species of animal. Dilatation of the heart, especially of the right side in guinea pigs, is com- 

 mon to all animals. Rigid distention of the lungs, which cannot be compressed except by 

 catheterization of the bronchi, is most marked in the guinea pig in acute shock. Hyperemia, 

 minute hemorrhages, and edema usually observed in both acute and subacute shock in other 

 animals are not severe in the distended lungs of acute shock in guinea pigs but present in 

 delayed shock. 



Microscopically, in the rigidly inflated lung there is marked distention of the alveoli, with 

 occasional rupture of their walls, constriction of the bronchi and frequently of the small 

 arteries. The secondary bronchi are likely to show edema in the lumina and in the surround- 

 ing tissue. The site of greatest muscular contraction was shown by Schultz and Jordan^ to be 

 in the secondary bronchi. The abdominal viscera are the seat of well-marked passive hy- 

 peremia. Gay and Southard^ describe fatty degeneration of the capillary endothelium near 

 small hemorrhages. Beneke and Steinschneider'' found Zenker's hyaline necrosis of skeletal 

 muscles, particularly those of respiration, which Wells believes is due to asphyxia. These 

 changes cannot be regarded as characteristic of anaphylactic shock. 



The distention of the guinea pig lung has been studied extensively. This animal has a 

 heavy bronchial and bronchiolar muscle and rather weak extrinsic respiratory muscles. It 

 seems to be more capable of inspiratory than expiratory effect. This may serve to explain 

 why at death the lungs are widely distended. Auer and Lewis^ state that the asphyxia is 

 "apparently produced by tetanic contraction" of the bronchiolar musculature. I have con- 

 firmed this statement, but in recent studies as yet unpublished have been impressed in addi- 

 tion by the edema described above. Pelz and Jackson^ have observed bronchoconstriction in 

 the dog, but we have never seen pulmonary distention comparable to that of the guinea pig. 



This reaction of smooth muscle has been found to be general. Schultz' demonstrated 

 that isolated intestinal muscle of the guinea pig normally sensitive to fresh serum is more so if 

 the animal has been rendered hypersensitive (anaphylactic). Dale,* subsequently confirmed 

 by Weil' and others, more conclusively demonstrated the fact in regard to the virgin guinea 

 pig uterus which is not sensitive normally to fresh serum. The same is true of the dog's 

 uterus (Manwaring et al.).^° Manwaring and his colleagues have shown that in the dog's 

 alimentary canal the most marked effects are in the colon and rectum. The urinary bladder 

 of the dog and guinea pig reacts strongly, but this is not true of the rabbit's bladder. The 

 blood vessels of the lungs of guinea pigs also react. The question of the reaction of hepatic 

 blood vessels will be discussed subsequently. 



' Gahringer, J. E.: /. Immunol., 12, 477. 1926. 



^ Schultz, W. H., and Jordan, H. E.: /. Pharmacol, fir Exper. Therap., 2, 375. 1911. 

 3 Gay, F. P., and Southard, E. E.: /. Afed. Research, 16, 143. 1907. 



"Beneke, R., and Steinschneider, E.: Centralbl.f. allg. Path. u. path. Anat., 23, 529. 1912, 

 5 Auer, J., and Lewis, P.: /. Exper. Med., 12, 151. 1910. 

 ^Pelz, M. D., and Jackson, D. E.: /. Lab. b' Clin. Med., 3, 387. 1918. 

 7 Schultz, W. H.: J. Pharmacol. &" Exper. Therap., i, 549. 1909-10. 

 "Dale, H. H.: ibid., 4, 167. 191 2-13. 



9 Weil, R.: J. Med. Research, 30, 87, 299. 1914; Proc. Soc. Exper. Biol. &• Med., 11, 86. 1914. 

 '"Manwaring, W. H., Hosepian, V. M., Enwright, J. R., and Porter, D. F.: J. rmmunol., 10, 

 567. 1925; Manwaring, W. II., and Marino, H. D.: ibid., 13,69. 1927. 



