Michiel ("Mike") de Lange qualified as a veterinarian (BVSc, UP) in 1936, together with his schoolmate H.P.A. de Boom*. He started his career as state veterinarian in Dundee during the East Coast Fever eradication campaign. After a few months he was transferred to Potgietersrust, however, where he was involved in the control of foot and mouth disease and also developed a lasting interest in nature conservation and wildlife diseases. In 1938 he was appointed research officer and head of the research station Nooitgedacht at Ermelo, where he was again responsible for the eradication of East Coast Fever. In 1947 he transferred to the pathology division at the Onderstepoort Veterinary Institute as researcher. Here he completed his DVSc on infertility problems in cattle, a study which he initiated at Nooitgedacht. He also lectured part-time to veterinary students, first in pharmacology and later in surgery/gynaecology. When the Faculty of Veterinary Science became independent in 1957 he remained with the Research Institute, first as Assistant Director and then as Deputy Director until his retirement in 1974. During this period he became involved in international and African liaison activities. He also played an important role in nature conservation as a member of the Advisory Council on Nature Conservation and the National Coordinating and Advisory Council for Fauna Research. He was furthermore instrumental in the establishment of artificial insemination as a means to improve the genetic composition of cattle in South Africa.