654 PHARMACEUTICAL BOTANY 
body, as the muscles of the arm of a blacksmith, results in greater 
development of that organ whereas the continued disuse of an 
organ results in its partial atrophy or degeneration. While 
these facts about the environment and the use and disuse of 
organs have been recognized in the lives of many individuals, 
Lamarck assumed that the changes brought about in an organism 
through use and disuse of organs were passed on to the descend- 
: ants. As an illustration of his theory he 
used the neck of the giraffe. He assumed 
the early ancestors of the giraffe were 
grazing animals and that a change in the 
} environment caused them to feed on the 
} leaves of trees. The present long neck 
was acquired, according to Lamarck, as 
the cumulative result of the inheritance 
of slightly greater neck-length brought 
about in each generation by reaching up 
SF persistently to browse upon higher 
Fic. 486.—Jean Baptiste Vegetation. 
de Lamarck (1744-1829) who His theory of the inheritance of 
: xicalgci petit eh tpl acquired characters is largely rejected by 
dividual in its lifetime are DlOlogists of the present day because of 
inherited by its offspring and the lack of convincing evidence. 
Feiss: anos changes. Tue Darwinian THEORY oF NAtTu- 
RAL SELECTION.—Charles Darwin 
(1809-1882) was an English naturalist, who made many observa- 
tions on the British exploring expedition that circumnavigated 
the globe on H.M.S. Beagle from 1831-1836. As an outcome of 
this experience and other later observations he worked out a 
theory of evolution which he published in 1859 in a book entitled 
“The Origin of Species by Means of Natural Selection,” or “The 
Preservation of Favored Races in the Struggle for Life.” 
Darwin’s Theory is based on the following fundamental 
propositions: 
1. PRODIGALITY oF Nature.—Living organisms are enor- 
mously fertile, yet the total number is approximately sta- 
tionary. It seems well established that many more offspring are 
produced by plants and animals than can actually survive. A 
