Loss of species is the key issue of conservation. Contrary to misuse of land which is visible to anybody with eyes to see, the issue of extinction is sly, treacherous, and open to clear perception only for experts. It touches on quality, and reaches far out in time: hard things to grasp for non-biologists. Thus an extra responsibility devolves on those who are in a position to know and to speak. The value of the genetic resource base has been set forth in e.g. the book by O.H. Frankel & E. Bennett, Genetic resources in plants (1970), and in the BIOTROP symposium edited by J.T. Williams e.a., South East Asian plant genetic resources (1975); Myers adds many striking facts: half the prescriptions in the U.S.A. contain a drug of natural origin. The cardiac drug reserpine, from Rauvolfia, costs $ 1.25 per gram to synthesize, $ 0.75 from natural sources. The anti-polio vaccin was developed in experiments in chimpanzees. The Amerindians in Amazonia know 750 medicinal plant species. Now the possibility of massive destruction of tropical forests — where most species are located — casts some frightening shadows on the future. The question how to cope with the threat appears to be connected with human ethics and the international order. Consequently, most publications on the subject suffer from a partial lack of maturity: don’t look to Myers for ethics, nor to the Routleys for biology. It seems therefore advisable that on the part of all disciplines a common fund of knowledge and insight be built up. In my efforts, great stimulation was received from correspondence with Dr. Willem Meijer (Botany, University of Kentucky, Lexington, Ky. 40506, U.S.A.), who in his disinterested manner never fails to come up with things true and shocking.