The unloading of oxygen from the blood 169 



But Ci is 43 mm., therefore 7\ would work out at 7 mm. As the 

 experimental error was not much more than 7 mm. the true value for 

 T. 2 cannot have been much above zero. 



This is not the point I wish especially to emphasise. The real 

 contrast between this experiment on muscle and those on the 

 salivary gland lies in the fact that in Period I the intra-cellular 

 pressure was 24 mm. below the venous oxygen pressure. 



100 



Exp. V Exp. VII 



FIG. 9Q.A l} A 2 , A 3 , oxygen pressure in arterial blood. V lt F 2 , F 3 , oxygen pressure in 

 venous blood. Cj, C 2 , C 3 , mean oxygen pressure in capillary blood. T lt T 2 , T 3 , 

 oxygen pressure in tissue, in two experiments on the gastrocnemius muscles. In the 

 first period the animal is breathing air, subsequently a mixture of oxygen and nitrogen 

 poor in oxygen. Ordinate = mm. pressure. The numbering of the experiments 

 follows that of Verzar's paper. 



To consider Exp. VII next. There are three periods in the 

 experiment, the following are the data tabulated on the basis of 



T, = : 



i ii in 



74 mm. 30 mm. 32 mm. 



0061 c.c. -0039 c.c. -0035 c.c. 



26 mm. mm. 4 mm. 



Period 

 C 



Q 

 T 



The figure four in the last column has, of course, no significance, 

 not differing materially from zero. If T s be assumed to be zero instead 

 of T 2 , T! would work out at about 20 mm., a figure which agrees 

 with that given by the independent method of calculation employed 

 by Verzar (1) . The highest computation for muscle is 27 mm.* 



* Value used on p. 178. 



