Lactic acid in mammalian cardiac muscle.— Part III. changes in hydrogen-ion concentration. (Preliminary note.)

Experiments have been made to determine (1) the hydrogen-ion concentra­tions of cardiac and skeletal muscle minced in the cold (a) under normal con­ditions, (b)after stimulation to fatigue, and (c) in rigor mortis, and (2) the change of hydrogen-ion concentration following the addition of known amounts of lactic acid. The measurements were made by means of the glass electrode method (Kerridge (1)). The results given are quantitatively only preliminary in character, pending (i) the repetition of the experiments on a larger number of animals, and (ii) the more accurate estimation of corrections due to dilution with saline, &c.