Water, sodium, potassium, and chloride content of skeletal muscle in fit and ill subjucts.

Biopsies of deltoid, gastrocnemius, or rectus abdominis taken under general anaesthesia from each of 15 subjects have been analysed for fat, water, sodium, potassium, and chloride. Some 110 samples were analysed for each muscle, and all the estimations were made on each sample. Standards have been constructed for the normal composition of these three muscles, and their reliability is discussed. Data from subjects with peptic ulcer, hyponatraemia, and sustained weight loss must be excluded from standards. It seems likely that standards could be improved by taking age and sex into account.