THE CIRCULATION 111 



stand obliquely above the vein. Record the blood-pressure. Release 

 the clip slightly and allow 1 to 2 c.c. of the solution of adrenalin to enter 

 the venous circulation. Make a mark upon the paper, indicating the 

 moment when the injection was made. 



Determine the length of the latent period intervening between the 

 injection and the rise in blood-pressure. Account for this interval. 

 Note the character of the reaction and explain its cause. 



What is the effect of adrenalin when applied to bleeding surfaces? 

 State why adrenalin is added to solutions used for purposes of infusion 

 after hemorrhage. 



FIG. 72. EFFECT OF ADRENALIN ON BLOOD-PRESSURE (Doo). 



Annotation. Since adrenalin deteriorates on standing, and especially when 

 exposed to light, its strength can only be determined in a physiologic way. Conse- 

 quently, adjust the dose to the reaction obtained, i. e., give it in smaller quantities 

 if the rise is excessive and if the heart-beats assume a pronouncedly diastolic char- 

 acter. 



5. Hemorrhage and Saline Injection. Heat a considerable quantity 

 of physiologic salt solution to 38 C. Draw 100 c.c. of this solution into 

 a pipet and connect the latter with the cannula in the jugular vein. 

 Record the blood-pressure. Bleed the animal through the femoral ar- 

 tery until the carotid pressure has fallen to about 50 mm. Hg. Allow 

 50 c.c. of saline solution to enter the venous circulation. What effect 

 is produced thereby? Repeat the injection until the pressure has be- 

 come normal. How large an amount of the solution has been injected? 

 Kill the animal by giving an excessive amount of ether. 



