108 ADVANCED LESSONS IN PRACTICAL PHYSIOLOGY 



blood-vessels of the posterior part of the body must cause a temporary 

 reduction in the quantity of the blood allotted to the head-circuit. 



6. Influence of Hemorrhage. Insert a cannula in the femoral artery. 

 While a tracing of the carotid pressure is being recorded remove the clip 

 from the femoral artery and allow 20 c.c. of blood to escape into a beaker. 

 Observe the systolic increase in the force of the ejection. Again apply 

 the clamp and allow the pressure to adjust itself. What factors are 

 involved in this compensation? Again withdraw 20 c.c. of blood, and 

 continue this procedure until the pressure has fallen to zero. Care- 

 fully observe the symptoms of excessive hemorrhage, as displayed by the 

 changes in the character of the respiratory movements and the rate and 

 force of the heart. How much blood has been withdrawn, and what 

 proportion of the total quantity present in this animal? Kill the ani- 

 mal by giving an excessive amount of ether. 



