HYPERSUSCEPTIBILITY 213 



violent general convulsions, marked inspiratory and expiratory effort 

 with cyanosis, exhaustion and death from respiratory failure with the 

 heart still beating. In the dog the respiratory and convulsive phe- 

 nomena are not so marked ; there is violent precordial activity, marked 

 fall in blood-pressure, diarrhea and vomiting. In man the phenomenon 

 may show predominance of the respiratory and convulsive symptoms 

 or of the cardio-vascular and the gastro-intestinal symptoms. Other 

 animals show variations of the general picture outlined. The necropsy 

 on a guinea-pig shows large, pale, distended lungs filling the thoracic 

 cavity, cardiac dilatation, particularly of the right side, passive con- 

 gestion of the abdominal viscera sometimes associated with minute 

 hemorrhages in the gastro-intestinal tract. The lungs may show con- 

 gestion, edema and small hemorrhages, but, as a rule, the distention 

 is so marked that there is little blood in these organs. Microscopically 

 there is marked distention of the alveoli, with rupture of their walls, 

 constriction of the bronchioles and frequently of the small arteries. 

 Gay and Southard describe fatty degenerative changes in capillary 

 endothelium near small hemorrhages, as well as fatty changes in heart 

 muscle, skeletal muscle and peripheral nerves. Beneke and Stein- 

 schneider found Zenker's degeneration particularly of the respiratory 

 muscles, but Wells believes this to be the result of asphyxia which pro- 

 duces Zenker's hyalin through the increase of lactic acid in the muscle. 

 In dogs and other animals the pulmonary distention is not marked ; the 

 important features are dilation of the heart, marked congestion and 

 multiple hemorrhages. None of these anatomical changes is charac- 

 teristic or to be distinguished from other toxic conditions. The pul- 

 monary distention is more distinctive than any of the other changes. 



From the functional point of view there have been extensive in- 

 vestigations of the distention of the lungs, the fall of blood-pressure, 

 fall in temperature, delayed coagulability of the blood and alterations 

 of the nitrogen metabolism. Auer and Lewis found that in guinea-pigs 

 death is due to asphyxia " apparently produced by tetanic contraction 

 of the smooth muscles of the bronchioles." This is independent of 

 pithing, section or degeneration of the vagus, and is therefore periph- 

 eral, either in the nerve terminals or the muscle itself. Auer has 

 shown that atropin reduces this effect, thus indicating the action upon 

 nerve terminals. Karsner and Nutt found that there is a definite 

 quantitative relation between the intoxicating dose of serum and the 

 protective dose of atropin and this fact, together with the protective 

 action of anesthetics such as ether, indicates that there may be factors 

 involved other than mere physiological antagonisms. The exciting 

 action on smooth muscle is not confined to the bronchiolar muscle for 

 Schultz demonstrated a similar action in vitro on smooth muscle of the 

 intestine and bladder of sensitized guinea-pigs and this has subsequently 

 been extended to include other smooth muscle such as uterus. Pelz 

 and Jackson have recently observed broncho-constriction in dogs during 

 the acute shock, but although this is severe we have been unable to 

 demonstrate acute emphysema in dogs. 



