Medical practice is enriched and mankind benefited by any procedure, prophylactic, diagnostic or therapeutic, by which the problems of disease can be more accurately approached. When Sir John Floyer adapted the watch for the counting of the pulse, he made the civilized world his debtor. The application of chemistry in the test for sugar in the urine has proved to be of enormous help to the physician. The simplified technic for the estimation of basal metabolism has opened new possibilities in clinical medicine. Human nature is not always easily swayed by interest in the novelties of science; but, when it is moved, the pendulum of enthusiasm is often more than likely to swerve too far in one direction before it regains the normal swing. One need but read the history of any new test, new instrumental procedure, new apparatus or new drug, to find abundant illustrations of this dictum.