WALTER E. GARREY 



51 



ture by the addition of cold water or ice to the large containers but the 

 variations in temperature were slight and negligible. 



With scrupulous care to avoid injury, the ganglion was dissected 

 from the heart and freed of all adventitious tissue, rapidly weighed, 

 and immersed in the fluid (pH 7.7) to wash away all possible trace 

 of acid and buffer. It was then placed in the tintometer tube at 

 the desired temperature and the time required to assume the tint 

 (pH 7.4) was determined with a stop-watch. 



Results. 



The results obtained in five experiments are presented in Table I. 

 The relative velocity of CO2 production is the reciprocal of the time 



TABLE I. 



Rale of Carbon Dioxide Production by Ganglia. 



in seconds required to change the tint of 3 cc. of solution from pH 7.7 

 to 7.4. The figures given are averages, usually of three readings, 

 which in the present instance did not vary more than 3 per cent from 

 the mean. 



The results shown in Experiments A, B, and C (Table I) are typi- 

 cal. The temperature coeflticient (Qio) is equal to or greater than 2, 

 in all except the highest range of temperature. The magnitude of 

 the coefficient is of the same order as that previously found by Garrey^ 

 for the rate of the heart beat. Another similarity to the effects of 

 temperature on rate of rhythm is to be found in the fact that it is 

 usual that transient exposure to temperatures as low as 4°C. so affects 



