Active Hypercemia. 401 



acid in shed blood by Evans (personal communication). The results obtained 

 are shown here : — 



Lactic acid 

 (mgrm. in 100 c.c. each of) 



Stimulation of 



Lingual nerve. 



Hypoglossal nerve. 



Plasma. 



Corpuscles. 



Plasma. 



Corpuscles. 



Dog 22 



„ 23 



6 24 



Mean 



16 -0 

 12 -5 

 8-0 



16 -0 

 12 9 

 8-8 



62 -0 

 18-4 

 16 -0 



68 -0 

 16 -0 

 20-8 



12-2 



12 6 



32 -1 



34 -9 



Taking into account the hsematocrite values of these bloods, the lactic acid 

 would appear to be evenly diffused through plasma and corpuscles. 



The corpuscles from exercised muscles seemed to show an acidity of their 

 contents markedly higher than the plasma in which they were laked even 

 when NaF was used as the anti-coagulant (vide infra). Two dialysing sacs 

 were prepared (Dale and Evans, 1920) and half filled with saline and water 

 respectively (both of known Pn and corrected for) and a comparison made of 

 the Ph ; such results as the following were obtained ■ — 



Dog 25. Dog 26 



Corpuscles intact (in saline) 7'35 7'40 



Euptured corpuscles (in distilled water) 7"20 7 - 25 



It must be mentioned, however, that laked corpuscles (frozen and thawed) 

 always exhibit a slightly lower Pn than intact corpuscles. 



An increase of lactic acid in the blood is thus seen to be not incompatible 

 with a rise of alkali reserve in the plasma, in view of the share played by the 

 corpuscles in bearing the onslaught of the acid attack. It must further be 

 admitted that the red corpuscle is permeable to the lactic acid ion, and the 

 following is advanced as a possible explanation of the events : — 



1°. Diffusion of the lactic acid from the working muscle into the alkaline 

 tissue fluid 



Lactic acid + NaHCOs — Sod. lactate + H 2 C0 3 . 



The carbonic acid given off diffuses through the vessel wall where it exerts 

 its vaso-dilator effect (vide figs. 4 and 17 ; note in the latter the direct 

 astringent effect and the indirect effect of lactic acid due to C0 2 ). 



2 F 2 



