June 20, 1928.
My dear Dr. Forkner,
I view with misgivings your apparent plans for overworking this summer, carrying on too extensive supravital studies along with Mallory's course.  Remember that you have worked hard all winter and need rest.
There is one point where human material will be of great significance to you and that is the testing with the oxydase stain of material from human podliteal and inguinal lymph glands.  Almost all human monocytes are oxydase positive, an occasional one negative; it thus becomes of great significance to determine whether the monocytes, if present in superficial human lymph nodes are positive or negative.  Be sure to take the Sato; Sekiya technique.  Wlater will give it to you.  The preparations must be stained the very day of the autopsy; it is useless to try the next day even.  The slides should be looked at within two weeks as they may fade.  McJunkin worked a lot on the oxydase, trying to show that the rabbit does not have monocytes at all comparable to the human on account of the negative oxydase in the rabbit monocyte.
Very cordially yours,