142 Chapter IX 



The following are the data yielded by a couple of experiments on 

 this subject. 



Oxygen used up in c.c. per grain of 



gland per minute 



, * > 



Resting Secreting (adrenalin) 



Exp. 1 0-028 0-052 



Exp. 2 0-026 0-050 



Speaking roughly the gland uses up about the same volume of 

 oxygen as it secretes of saliva. 



The relation between the oxygen used by the gland and the flow 

 of blood and of saliva may be studied in rather greater detail in such 

 an experiment as that represented in Fig. 77. 



The variations of oxygen consumption were estimated at different 

 times during and subsequent to the secretion of saliva produced by 

 an injection of adrenalin the moment of taking the samples for 

 analysis, the rate of flow of the blood in each case, and the rate of 

 flow of the saliva are all shown in the figure. The quantities of 

 oxygen used were as follows. Taking the amount of oxygen used by 

 the resting gland (Sample I) as unity, the amounts used at different 

 times indicated in the figure are found by analysis to be 



Sample II IV V VI 



Eatio of oxygen used to that of resting gland ... 1-2 2-1 3'7 1*3 



Moreover it is very interesting from our present point of view to 

 see that the heightened metabolism of the gland, like the heightened 

 blood-flow, outlasts the flow of saliva by a considerable time, and 

 outlasts the obvious direct vascular effects of the adrenalin by still 

 longer. 



We have shown that there is dilatation of the arteries when 

 metabolism is induced by adrenalin, can we as a control experiment 

 prove that adrenalin produces constriction and constriction only when 

 there is not increased activity of the cells ? The following facts may 

 be cited in this connection. In the surviving gland, as in other per- 

 fused organs, the effect of drugs on the vessels survives the effect on 

 the organ itself. Adrenalin added to the saline which perfuses the 

 vessels of the submaxillary, a couple of hours after the death of the 

 animal, produces no secretion of saliva and protracted constriction of 

 the vessels ensues without the least vestige of dilatation ; this effect 

 may even be obtained on the following day. 



The following example may be cited of a cat's submaxillary gland, 

 which was perfused directly through the submaxillary artery. 



