The coefficient of diffusion of lactic acid through muscle

Abstract

In a recent paper from this laboratory, Stella (1) described experiments relating to the diffusion of inorganic phosphate through muscle. The upper legs of a frog, fresh or in any required stage of fatigue, were suspended at time zero in an excess of Ringer's solutions, and at various times t thereafter the phosphate content of the solution was determined. It was assumed that the diffusion obeys the equation P = 2 c √ kt/π where P is the number of milligrams of phosphate diffusing across 1 sq. cm. of the outer surface of the muscles employed, c the initial concentration of the phosphate in milligrams per cubic centimetre, k the coefficient of diffusion (cm. 2 /min.), and t the time of diffusion in minutes. The mean value of k determined from the observation was 5 x 10 -6 , which is far less than of analogous from the observations was 5 x 10 -4 , for sodium formate 5 x 10 -4 , for potassium carbornate 4.2 x 10 -4 . The small value of k showed that diffusion of phosphate through the fibres is far slower than in free solultion.