Robertson: Theories of Evolution. 169 
is that even if he threw out these suggestions and then retracted 
them for fear of annoyance, or even persecution from the bigots 
of his time, he did not himself always take them seriously, but 
rather jotted them down as passing thoughts.’ 
Il.—ERASMUS DARWIN AND LAMARCK. 
The germs of the doctrine of Descent with Modification seem 
to have been in the atmosphere in the last decade of the eight- 
eenth century, for between 1790 and 1800 the conclusion that 
species were not immutable was reached independently in 
Germany by Goethe, in France by Geoffroy Saint-Hilaire, and in 
England by Erasmus Darwin. The last named, who was a 
physician, a poet, and grandfather of Charles Darwin, published 
in 1796 a remarkable book called ‘ Zoonomia,’ which contained, 
amidst much speculation irrelevant to our purpose, a profession 
of faith in the doctrine of evolution. After discussing the 
metamorphoses which individual animals undergo, and_ the 
essential likeness of structure of all the higher animals, he 
goes on to say, ‘would it be too bold to imagine, that in the 
great length of time, since the earth began to exist, perhaps 
millions of ages before the commencement of the history of 
mankind, would it be too bold to imagine, that all warm-blooded 
animals have arisen from one living filament, which THE GREAT 
FIRST CAUSE endued with animality.’ 
Erasmus Darwin not only believed in evolution, but tendered 
one or two suggestions as to ow the process had been brought 
about. His main idea was that useful modifications, such as 
the hard beaks of certain birds, the elephant’s trunk, and the 
rough tongue and palate of cattle, ‘seem to have been gradually 
acquired during many generations by the perpetual endeavour 
of the creatures to supply the want of food, and to have been 
delivered to their posterity with constant improvement of them 
for the purposes required.’ He also foreshadowed the theory of 
Sexual Selection, which we shall have occasion to speak of later 
in dealing with the work of Charles Darwin. The fact that these 
suggestions of Erasmus Darwin met with little recognition at 
the time is scarcely surprising when we remember that they 
were put forward more or less casually, and that no effort was 
made to establish them by proof. 
The name of the French biologist Lamarck, who first 
published his views at the beginning of the nineteenth century, 
is better known in the history of evolutionary thought than that 
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