CLOSING THE DOOR ON DEVRIES,HUGO MENDELISM

Recent studies have shown that Hugo de Vries did not rediscover Mendel 's laws independently and that the classical story of the rediscovery of Mendel is largely a myth. Until now, however, no satisfactory accou nt has been provided of the background and development of de Vries' vi ews on heredity and evolution. The basic tenets of de Vries' Mutations theorie (1901-1903) and his conception of Mendelism are still insuffic iently understood. It has been suggested that de Vries failed to assim ilate Mendelism and that he wrote his Mutationstheorie in a state of c onfusion. In this paper I argue that we can arrive at a better underst anding by adopting a more symmetrical approach. My analysis will conce ntrate on three important aspects of de Vries' thinking which have bee n insufficiently appreciated until now. The first is that de Vries' re ading of Mendel compelled him to change his conception of the heredita ry particles, the pangenes, in a fundamental way. The second is de Vri es' use of the notion of 'hereditary force'. The third revolves around de Vries' typological species concept, which has been the source of m uch confusion in the literature. I shall conclude that de Vries did su cceed in incorporating 'Mendelism' into his wider views on heredity an d evolution, and that he did manage to handle his evidence in a consis tent way. Yet I shall also conclude that Mendelism, in de Vries' inter pretation, had nothing to do with 'normal' heredity and was mainly a l aboratory phenomenon.