The call for oxygen by the tissues 



99 



It must however be remembered that these results were obtained 

 by methods which are now quite out of date ; moreover the presence 

 of CHC1 3 in the blood may have caused some inaccuracy unsuspected 

 at the time. 



The more recent developments of the discussion of the relation 

 of activity to oxygen used, as in the case of striped muscle, have 



250-TTT300 



350 400 45O 500 550 600 



FIG. 57. Ordinate = volume of oxygen used in c.c. per minute. Abscissa = time in seconds. 

 Upper signal = duration of flow of saliva. Lower signal = duration of chorda stimula- 

 tion. I, short stimulation. II, long stimulation. Ill, fatigued gland. 



gone to show that the oxygen is not used entirely at the time of the 

 secretion, but that it continues to be used for some little time after- 

 wards. This is not only so in the case of stimulation of the chorda 

 tympani, but it is also the case when saliva is elicited by the injection 

 of adrenalin. The experiments have been done on the cat. 



Fig. 57 I, II and III shows the relation in time between the flow 



72 



