HYDE: EXPERIMENTS ON THE SKATE. 



35 



strangely enough does not affect the respiratory center in the 

 same direction but rather depresses its force and rate, as well 

 as the rate of the heart's activity. But a 2m solution has again 

 a like depressing influence upon both force and rate of respira- 

 tory and cardiac rhythm and at first causes a rise in blood pres- 

 sure. 



Curve 1. Following an injection of m% NaCl. 

 heart and gill arch. 



Lever attached to 



rnmW 



Before After 



m 



Upper, respiration. Lower, cardiac curve. Injection at X. Force of 

 heart and respiratory action increased, but not rate. 



Curve 2. After NaCl. Lever attached to heart and gill arch. Normal 

 before X. 



L 



Upper, respiration. Lower, cardiac curve. Heart and respiratory 

 rate unchanged; force of former increased but of latter unchanged or 

 even less. Time, five seconds. 



Data of the mean results in respiration, heart action and 

 blood pressure of many experiments on the skate. Different 



