The following letter, which explains itself, was sent to Drs. R. C. Cabot, W. B. Cannon, Joseph Erlanger, A. W. Hewlett, Theodore C. Janeway, Yandell Henderson, A. D. Hirschfelder, H. C. Moffitt and R. L. Wilbur.
In a series of functional heart tests recently undertaken in the Students' Infirmary upon students entering the University of California a large number of determinations of blood pressure were made. Since graphic records were desired, the Erlanger blood pressure apparatus was used; and while it was writing on the smoked surface a record of the pressure oscillations in the cuff, a float in a large U-tube of mercury was writing on the same surface a continuous record of the actual amount of pressure in the cuff as it was gradually falling. (Fragments of these manometric tracings will be noticed in the photographs I am mailing to you, and the others to several