162 



Chapter X 



furnished by the submaxillary gland. We start with (1) the arterial 

 blood, (2) the venous blood from the resting gland, (3) the venous 

 blood from the secreting gland. Can we tell the oxygen pressure in 

 all three of these? 



Analysis gave the following data : 



(1) The arterial blood was 94/ saturated with oxygen. 



(2) The venous (resting) blood was 59 % saturated with oxygen. 



(3) The venous (active) blood was 66 % saturated with oxygen. 

 From these we could infer the pressures of oxygen if we knew the 



dissociation curves. The curves are probably all different since the 

 carbonic acid pressures may be supposed to be different, and possibly 

 60. 



25 30 35 40 " 45 50 55 60 

 FIG. 87. Ordinate = quantity of C0 2 taken up by blood in c.c. per 100 c.c. of blood. 

 Abscissa = pressure of C0 2 . The points O correspond to the actual quantities of C(X 

 found in the samples of arterial venous and resting bloods. From these points the 

 C02 pressures are inferred. 



other acids are introduced in varying quantities. We do not know 

 the carbonic acid pressures nor the concentrations of other acids 

 present we have available data however concerning the quantity 

 of CO 2 in each sample of blood which is as follows : 

 (1) Arterial 100 c.c. blood contains 36 c.c. CO 2 . 



Venous (resting) 44 c.c. C0 2 . 



Venous (active) 29 c.c. C0 2 *. 



"* The venous blood coming from the active submaxillary gland is often anomalous 

 in that it yields less C0 2 when treated with acid than the arterial blood. The large 

 quantity of C0 2 and carbonates which are being discharged from the gland in the 

 saliva account for this phenomenon. 



