A Note on the Cardiac Output of a Single Individual Observed Over a Period of Five Years

reported the results of a study of the output of the heart in normal resting adults. At that time we commented on. the fact that two of our subjects differed in the degree of variation exhib- ited by their cardiac outputs at different times but under identical circumstances. We reported four observations of one individual whose cardiac output varied from 4540 to 6780 cc. per minute and five observations of another subject in whom five measurements scattered over a year varied only from 3700 to 3960 cc. per minute. Since that time further observations of the second subject have been made, with results which seem of interest sufficient to warrant record- ing them.