Cause of Serum Anaphylactic Shock. 33 



being exposed, scarcely collapsed ; they almost, indeed, fill the 

 chest cavity. They found that the lungs are pink and float lightly 

 on water ; pieces cut off remain distended, the cut surfaces being 

 moderately dry when pressed give up considerable air. This im- 

 mobility of the lungs in a more or less inspiratory condition they 

 think is due probably to a tetanic contraction of the musculature 

 of the fine bronchioli and alveolar ducts, imprisoning the air in the 

 alveolar sacs, and that a slight degree of pulmonary edema aids 

 in the production of this pulmonary inspiratory immobility. They 

 also show that subcutaneous doses of 0.5 to 1 mg. of atropin sul- 

 phate administered a few minutes previous to the killing dose of 

 horse serum abolishes the pulmonary symptoms or greatly reduces 

 them. 



Thus far our work confirms their description of the pulmonary 

 symptoms. We find that the lungs of pigs that die in from two to 

 five minutes after injecting intravenously 0.5 c.c. of horse serum, 

 are almost invariably pink, full of air, and the pulmonary blood 

 vessels filled with blood so that if immediately after death the lungs 

 be punctured with a lead pencil or probe, a copious flow of black 

 venous blood results. The lungs if cut from the chest cavity re- 

 main distended and when squeezed much air and some liquid exude. 

 Out of all the controls that died in from two to five minutes there 

 was no exception to this rule. When pigs die after a longer time 

 than five minutes, the lungs do not as a rule remain completely 

 distended and do not always fill the chest cavity completely. It 

 may almost be said (judging from the experiments thus far per- 

 formed) that after the killing dose of serum the duration of life is 

 more or less proportional to the amount of collapsible lung area 

 left just before death. A pig then that lives more than five minutes 

 can be made to live still longer by means that will be mentioned 

 in the following paragraph. 



The condition of partial lung immobilization can be initiated by 

 certain drugs that are known to act upon smooth muscle. Atro- 

 pin in small doses (.01 mg. per gm. of body weight) proves very 

 serviceable in hindering the anaphylactic action of the serum- 

 Thus far we have found chloral hydrate and adrenalin even more 

 effective in desensitizing the lungs towards the second injection of 

 serum. And when oxygen is given before the second serum in- 

 jection, the lungs thereby being, previous to the injection, loaded 



