Opposing these Neo-Lamarckians were such prominent scientists as August Weismann, A.R. Wallace, E. Ray Lankester, who strenuously opposed the idea that "acquired characters," or more precisely _parental experience_, are ever transmissible. In the subsequent years the greatest variety of experimental tests have been applied to secure the hereditary transmission of any sort of such acquired characters, with uniformly negative results. One of the most elaborate of these experiments was conducted by a German botanist, who transplanted 2,500 different kinds of mountain plants to the lowlands, where he studied them for several years alongside their relatives, natives of these lowlands. He found that their mountain environment had made absolutely no permanent change in their structures or habits, which soon conformed exactly with those of their relatives which had lived in the lowland environment for centuries. Many similar efforts have been made to confirm this doctrine of the transmission of acquired characters; but their universal failure is like that of mechanics in trying to invent perpetual motion. Thomas Hunt Morgan sums up the present situation in the following words: "To-day the theory has few followers among trained investigators, but it still has a popular vogue that is wide-spread and vociferous." And we may add that the extent of its spread is directly proportioned to the need felt for this doctrine as a support of the theory of evolution, while the vociferance of its advocates is inversely proportioned to the evidence in its support. As a result of extensive modern experiments and discussion, biologists have grown very cautious, and are by no means so positive as they were twenty years ago in affirming just _how_ species have come into existence. Echoes of this old controversy between the two leading schools of biologists are occasionally heard; but the enthusiasm with which they set out a half century ago to solve the riddle of plant and animal life has largely given way to a purpose to discard speculation and patiently to observe and record actual facts. For with natural selection discredited in the house of its friends, and Lamarckianism under grave suspicion from want of a single well authenticated example, it is hard to see what there is left of the biological doctrine that has so dominated scientific thought for a half century. If each of these opposed schools of scientists are right in _what they deny_, the whole theoretical foundation for the origin of new kinds of animals and plants is swept away,--absolutely gone. For if an individual really cannot transmit what he has acquired in his lifetime, how can he transmit what he has not got himself, and what none of his ancestors ever had? And if natural selection cannot start a single organ of a single type, what is the use of discussing its supposed ability to improve them after the machinery is all built? II