The following investigations were carried out when the writer was research assistant to the Research Expeditions sent to Western Samoa in 1953 and 1954 by the Medical Research Council of New Zealand. The members of these expeditions were Dr. D.D. McCarthy, Mr. M.J. Marples, Mr. D.F. Bacon and Mr. N. Fitzgerald. Part of this thesis has been published (McCarthy & Fitzgerald 1955) and part is incorporated in the N.Z.M.R.C. Report of the Expedition to Western Samoa in 1951.