380 



Dr. S. W. Patterson. The Antagonistic 



by Hans Meyer, and using a eardiometer attached to various forms of 

 recorder, it was found that the output as measured was not increased, 

 although in some instances the recorder showed an increased amplitude 

 of stroke. Since the output through the coronary system is not increased, 

 the difference between these results and those of Jerusalem and Starling (4) 

 probably lies in the inadequacy of the volume recorder used by them, which 

 responded to the slower rhythm by a greater throw.* On the other hand, 

 cats are remarkably tolerant of CO2 as compared with dogs ; and it is of 

 interest to note that, in the only experiment with dogs recorded by these 

 authors, the output was much reduced by administering CO2. 



Adrenalin alone reduced the systemic output, but when adrenalin and 

 C0 2 were used together the effective output was hi some cases higher than 

 in the normal preceding period. 



Table IV.— Cat. Heart weight, 12 grm. 



Temp. 



B.P. 



I.V.C. 



Rate 

 10 sees. 



Output 

 10 sees. 



Output beat. 











c.c. 



c.c. 





36° C. 



73 



5 



37 



20 



0-54 







73 



8 



28 



20 



0-71 



5 -5 per cent. C0 3 . 





72 



4 



36 



21-5 



0-58 





72 



10 



30 



20 -4 



0-68 



10 -5 per cent. CO;,. 





70 



5 



34 



20 -8 



0-61 





70 



20 



22 



19 -2 



0-87 



17 -5 per cent. CO;,. 



34° 



108 



8 



33 



14 



0-425 







-8 c.c. adrenalin, 1/10000. 











100 



18 



47 



7 



0-149 







105 



24 



45 



13 



-29 







104 



18 



40 



13-1 



0-32 



17 per cent. C0 2 . 





104 



28 



49 



13 



0-26 





104 



12 



39 



13 



33 



18 per cent. C0 2 . 





105 



20 



46 



13 -5 



0-29 





106 



15 



34 



14 -3 



0-42 



20 per cent. C0 2 . 



Heart Rate. — With all percentages of C0 2 in the inspired air there is a 

 slowing of the heart rate, and this retardation becomes more marked as 

 the percentage of CO2 is increased. The slowing sometimes lasts for a time 

 after the CO2 is taken off and ordinary air respired again. 



Adrenalin causes, under all conditions, a quickening of the heart rate. 

 With inhalation of CO2 combined with the injection of adrenalin, the 

 algebraical sum of the above effects is noticed. Sometimes during the 



* Ketchain, King, and Hooker (11) found no increased output in the isolated cat's 

 heart. 



