WALTER E. GARREY 



165 



Results. 



The results of several typical experiments are summarized in Table 

 I. The normal values for the time required to produce the change in 

 pH are obtained before and after stimulating the inhibitory nerves 

 and compared with the corresponding time while the stimulation is 

 maintained. Differences in the time normally required by the dif- 

 ferent preparations to produce the change are due in part to differences 

 in the size of the ganglia and in part to inherent differences in the 



TABLE I. 

 Rate of CO2 Production, before, during, and after Stimulation of Inhibitory Nerves. 



intensity of the processes of CO2 production. The results obtained 

 by these experiments deal essentially with relative rates of CO2 pro- 

 duction, no attempt having been made to determine absolute values 

 for the amount of CO2 produced. 



Analysis of the experiments leaves no doubt that inhibition of the 

 automatic cardiac ganglion is a process involving a well marked 

 depression of the CO2 production in the ganglia (20 to 60 per cent of 

 normal) . The fact that the carbon dioxide production is only retarded 

 and not completely suppressed is probably due to incomplete inhibi- 

 tion or to escape from inhibition toward the end of the period during 

 which the determination is being made, since it has always been 



