In a recent publication1 two of us reported the results of two series of experiments on the isolated perfused heart. Based on these studies we have developed the conception that in the development and propagation of the excitatory process in the heart, the pH of the fluid bathing its tissues is a controlling factor. It is considered that the process of excitation is intimately concerned with changes in the state of equilibrium across the cell membrane. In harmony with the hypothesis advanced by Hermann,2 Brunings,3 and Bernstein,4 and more recently elaborated by Lillie,5 it is suggested that these changes have to do with alterations in the state of polarization existing at the cell tissue fluid interface. The propagation of the excitatory process by means of adjacent tissue by the action current developed at each excited point constitutes "conduction."
It is the purpose of this paper to indicate the possible application