THE CONTROL OF THE RESPIRATION 



351 



eter was made to record its movements on a drum, so that an accurate 

 record of the depth and frequency of the respirations was secured. Sam- 

 ples of air were removed from the bottle by ground-glass plunger syringes 

 at frequent intervals during the time that the animal was respiring into 

 the tubing. 



SOQ 



400 



300 



ZOO 



rot 



2, 



Fig. 129. Composite curve obtained from the data on sixteen experiments, showing the re- 

 spiratory response to COa in the decerebrate cat. Abscissae = percentage of CO2 in the inspired 

 air. Ordinates = the percentile increase the tidal air per minute. (From R. W. Scott.) 



The results are given in the accompanying curve (Fig. 129), which shows 

 that there is a perfect correspondence between the C0 2 percentage in the 

 air of the bottle and the pulmonary ventilation. Moreover, when the 

 bottle was filled with 2 instead of air to start with, the same results 

 were obtained, showing that the C0 2 accumulation alone was responsible 

 for the hyperpnea. In these cases the percentage of 2 remaining in the 



