188 PLANT PHYSIOLOGY AND ECOLOGY 



its almost universal acceptance. Bacon, ^ in his "Natural His- 

 tory" (1658), seems to have been the first to state that one kind 

 of plant may change into another through transmutation. Among 

 the causes of the latter he mentions drouth especially, further 

 pointing out that it does not act if the earth be moist. His 

 greatest achievement, however, was in anticipating in definite 

 though crude fashion the methods of experimental evolution, as 

 shown by his six rules for making one plant change into another. 

 One of these was "to take marsh herbs and plant them upon the 

 tops of hills and champaigns, and such plants as require much 

 moisture upon sandy and very dry grounds." Another was "to 

 make plants grow out of the sunshine, since this was a great change 

 in condition, and might bring about a change in the seed." Bacon's 

 ideas, though many were necessarily crude and incorrect, indicate 

 clearly that he had observed the origin of new forms by adaptation 

 to the habitat, and believed that such forms could be produced 

 experimentally. 



The first writer whose views on evolution attracted serious atten- 

 tion was Lamarck.2 His ideas were first advanced in 1801, and 

 further enlarged and revised in 1809 and 1815. He was the first 

 to point out clearly that all species have descended from other 

 species. Lamarck believed that new forms arose in three ways: 

 by the direct action of the habitat, in consequence of the use and 

 disuse of parts, and through crossing of existing forms. He held, 

 moreover, that evolution takes place in conformity with the law 

 of progressive development, and, to explain the universal presence 

 of simple forms, he assumed that these are arising constantly out 

 of non-living material. Within recent years, many of Lamarck's 

 views have been widely adopted by biologists, who are accordingly 

 known as Neo-Lamarckians. Saint-Hilaire ^ in 1828 reached the 

 conclusion that the species of to-day have descended from earlier 

 ones through the modification of the latter. He regarded the 

 habitat as the cause of change, as is clearly shown by his state- 

 ment that "specific characters remain fixed for each species as 

 long as the latter grows under the same conditions: they are modi- 

 fied in case the habitat undergoes a change." 



204. Darwin and the Origin of Species. The preceding account 



* Bacon, Francis. Sylva Sylvarum or a Natural History, 110, 1658. 



^ Philosophie Zoologique, 1809. 



^ Sur le Principe de I'Unite de Composition Organique, 1828. 



