J. A. Broomhead

The John Curtin School of Medical Research, Australian National University, Canberra, A.C.T., Australia.

F. P. Dwyer

The John Curtin School of Medical Research, Australian National University, Canberra, A.C.T., Australia.

J. W. Hogarth

University of Sydney, Sydney, N.S.W., Australia.

Robert E. Sievers

The University of Illinois, Urbana, Ill.

Eugene G. Rochow

Harvard University