140 



THE CIRCULATION OF THE BLOOD 



can be tolerated before cardiac embarrassment ensues. After the dis- 

 continuance of the > saline injection, the blood pressure returns very 

 rapidly to its old level. The most striking result of such experiments is 

 the enormous volume of saline solution which can be slowly injected 

 without perceptibly affecting the pressure. The question is, Where does 

 the fluid go ? If the urinary outflow is examined, a certain increase will 



Fig. 30. Composite curves to show effects on blood pressure of hemorrhage, and transfusion 

 with various solutions (N. M. Keith, from P.ayliss). The average pressure in the various experi- 

 ments before and after hemorrhage is given on the left in a continuous line. The behavior of the 

 pressure after transfusion varied according to the solution used. 



