During the period Bonsma was a post-graduate student in Dr J L Lush's class at Iowa State University 1935-1936,he became aware of classic research on breeding discase-resistant plants and animals so that when he was put in charge of Mara and Messina research stams in 1937, he was cognizant of this work. In a paper by Bonsma, Fanning in South Africa, February 1944, Reprint 13, "Hereditary Heartwater-resistant Characters in Cattle Bonsma reviewed some of the literature on this subject, because most cattle that died in the tropical and sub-tropical ranching areas in the Southen1 hemisphere died as a result of tick-borne diseases. In 1944 Bonsma wrote as follows: "1110 success achieved in the breeding of plants possessing a high degree of resistance to diseases is to be attributed to the application of methods based on the principles of genetics. Farm animals fortunately also possess hereditary characters conferring on them a higher degree of resistance to certain diseases. Unfortunately, however, little has hitherto been done in the way of applying this knowledge experimentally in the control of diseases in animals. Considerable attention is, on the other han<l, admittedly being given to the organisms cause diseases and to clinical measures for their control. As a result of the success attained by the use of vaccines and the hypodermic needle, the possible control of certain diseases by hereditary selection is frequently lost sight of. During the past few years, the interest taken in the breeding of animals possessing a higher degree of resistance to certain diseases, has been stimulated as a result of the achievements of plant breeders in the breeding of plants resistant to certain parasites and diseases. Most breeders of animals are of the opinion that the process by which it will be possible to breed nnima1s possessing a higher degree of resistance to certain diseases prevalent in certain areas, will be too slow and too expensive for general adoption.