12 6 JOHN T. HALSEY 



primary rise* followed by a fall in pulmonary and systemic blood-pressure, 

 attributed by them mainly to action on the arteries. In cats they usually 

 obtained a rise of pressure in both systems due chiefly to increased cardiac 

 output, but small doses were followed by a fall in both systems, which 

 must be due to arterial dilatation. In dogs there was a marked rise of 

 pressure in both systems, attributed largely to increased output. It is 

 evident from the above that our knowledge as to the changes in the pul- 

 monary circulation produced by epinephrin is very unsatisfactory. As in 

 the treatment of hemoptysis, epinephrin is almost always given hypo- 

 dermically, its effects must be similar to those produced by very small doses 

 given intravenously. The laboratory evidence, therefore, would indicate 

 that when thus administered it dilates the pulmonary vessels. 



Locally applied to mucous membranes and open wounds, or injected 

 under the skin, epinephrin causes marked vasoconstriction, which is 

 usually followed after a time by marked vasodilatation. 



Blood. Laboratory workers early noticed that in experiments in 

 which epinephrin was injected the blood frequently coagulated in the 

 cannuhie, indicating an increased coagulability of the blood. That this is 

 actually so was later demonstrated by Eichards and Vosburg, and by 

 Cannon and Mendenhall. 



Respiratory System. The most striking and clinically most important 

 action of epinephrin on this system is its power of preventing or relaxing 

 spasm of the bronchial muscles (Januschke and Pollak). Following in- 

 travenous injection of moderate doses, there is evidence of stimulation of 

 the respiratory center, while after large doses this center is depressed. 

 In laboratory experiments large intravenous doses, or smaller ones fre- 

 quently repeated, often cause pulmonary edema. 



Alimentary Canal. The local astringent effects may be obtained in 

 the mouth, esophagus, stomach, and rectum. When injected intravenously, 

 the motor functions of stomach and intestines are inhibited, just as if the 

 splanchnic nerves were stimulated. It is of interest that doses insufficient 

 to affect the blood-pressure produce this effect, but the practical importance 

 of this fact is lessened because of the evanescence of this action. Yukawa 

 found that oral administration markedly increased the secretion of hydro- 

 chloric acid, while Rogers, Kahe, and Ablahadian found that this secre- 

 tion was diminished after intravenous injection of suprarenal extract. 



Uterus. The effect of epinephrin on the uterus varies with different 

 sjx'cies and with the state of the organ (whether pregnant or not). This 

 variability in its action runs parallel with the varying effect of sympathetic 

 stimulation under like conditions. They both cause powerful contractions 

 of the pregnant uterus, and also (in some species) of the non-pregnant 

 uterus. In the virginal uterus of the cat or dog, on the other hand, epi- 

 nephrin causes relaxation (Kehrer). Stewart (1912) has shown that in 

 very small dosage epinephrin causes relaxation. 



