UNCLASSIFIED_ the Commission, in which case actual costs are fully reimbursed. There are, of course, situations in which such a distinction cannot be nicely drawn and an administrative judgment must be rade. In practice, however, this refined rule of thumb seems to have worked very well, and while there has been some resistance to accepting it, there has been no difficulty in applying it. Our next meeting is to be held at the Argonne National “Laboratory on March 13 and 14, which dates we hope will coincide “with the dedication of the new Argonne Cancer Hospital. Very truly yours, /s/ Alan Gregg, M.D., Chairman, Advisory Committee for Biology and Medicine