The Darwin- Wallace Centenary ' 
By Sir GAVIN DE BEER 
Director, British Museum (Natural History) 
FROM SPECIAL CREATION TO TRANSFORMISM 
ONLY ONE HUNDRED YEARS have gone by since the concept of evolu- 
tion was brought to the attention of thinking men in a manner which 
has compelled its acceptance. The demonstration that the members 
of the plant and animal kingdoms are as they are because they have 
become what they are, and that change, not immutability, is the rule 
of living things, is one of the most important contributions ever made 
to knowledge, and its effects have been felt in every field of human 
thought. 
That plants and animals constitute natural kinds, or species, had 
become clear by the end of the seventeenth century, when John Ray 
defined them as groups of individuals that breed among themselves. 
In general, species were accepted as being the result of special creation 
in each case, and there was little incentive to inquire further. 
In the eighteenth century doubts began to arise concerning the 
immutability of species. Some philosophers arguing theoretically, 
and a small number of naturalists who encountered difficulty in dis- 
tinguishing between varieties of cultivated plants and of domestic 
animals, which were recognized as the diversified products of species, 
found difficulty in accepting the view that species were unchangeable. 
Some naturalists, including Linnaeus himself in his later years, 
adopted a compromise, allowing that species could have descended 
with modification from genera, but that genera were immutable. 
With the increase in detailed knowledge of the flora and fauna of 
the world consequent upon the final stages of exploration, the problem 
of the distinction between varieties and species became acute. With 
boldness, and a breadth of vision amounting to genius, the French 
naturalist Lamarck cut the knot by proclaiming that there was no 
essential difference between species and varieties, that both species 
anid varieties were subject to change, and that “transformism,” not 
1 Reprinted by permission from Endeavour, vol. 17, No. 66, April 1958. 
333 
