126 IOWA ACADEMY OF SCIENCE 



The experiments of Henderson, Porter, Seelig and others show that 

 the condition of the artery in shock is one of extreme constriction and 

 the low blood pressure is the result of a venous stasis brought about 

 by venous dilatation from a loss of tonus in the venous wall. 



The use of epinephrin, or under the proprietary name adrenalin, has 

 been widely recommended in conditions of shock because of its stimu- 

 lating effect upon* the circular muscle of the arterial wall, constriction 

 of the vessel follows this stimulation and an elevation of the blood 

 pressure is thus brought about. 



Under the extreme condition of arterial constriction described by 

 Prof. Henderson to exist in shock, the beneficial effects of epinephrin 

 must be accounted for in some other way than by any action upon the 

 already over constricted artery. In the discussions upon the effect 

 of ephinepherin in causing a rise of blood pressure its action upon the 

 arterial wall alone as has been considered and we have found no state- 

 ments as to its effect upon the venous wall although we find smooth 

 muscle here as in the artery but of course not to anything like the 

 amount. To obtain some direct evidence as to the action of epinephrin 

 upon the vein and thus possibly upon the blood pressure the following 

 experiments were undertaken : 



From an anesthetised dog rings % inch wide were cut from the 

 external jugular vein. Two such rings of the vein were used at a 

 time, one for control and one to show the action of the drug. The 

 rings were connected to light writing levers in such a way that any 

 contraction as would produce a constriction of the vessel would cause 

 an elevation of the writing point and this would be recorded upon the 

 surface of a smoked drum revolving at a very slow speed. The time in- 

 volved from the removal of the tissue until the proper connections to 

 the writing lever had been made and the tissue immersed in the whipped 

 blood of the same animal was not more than two or three minutes and 

 the tissue was still irritable and free from post mortem changes. 



After imersion a record of the position of the two levers was made 

 lasting for from 2 to 8 minutes in different experiments. After thus 

 establishing a normal, quiet condition in the two rings a few drops of 

 a 1-1,000 solution of adrenalin was added to the blood containing one 

 of the immersed rings of the vein. The concentration of the adrenalin 

 in blood was about 1-100,000. The curves in figures I and II show a 

 rather sudden elevation of the lever following a latent period of about 

 one minute after the addition of the epinephrin and the contraction 

 lasting for an indefinite period before relaxation took place. Upon 

 direct inspection of the vein we found it contracted so as to have a 



