272 Colour and the Struggle for Life 
dioecious flowers ; but it is well to remember that their colours may 
be as unimportant to them as those of a gall, or, indeed, as the colour 
of an amethyst or ruby is to these gems’.” 
Incidental colours remain as available assets of the organism ready 
to be turned to account by natural selection. It is a probable specu- 
lation that all pigmentary colours were originally incidental ; but now 
and for immense periods of time the visible tints of animals have been 
modified and arranged so as to assist in the struggle with other 
organisms or in courtship. The dominant colouring of plants, on the 
other hand, is an essential element in the paramount physiological 
activity of chlorophyll. In exceptional instances, however, the shapes 
and visible colours of plants may be modified in order to promote 
concealment? 
Teleology and Adaptation. 
In the department of Biology which forms the subject of this essay, 
the adaptation of means to an end is probably more evident than in 
any other; and it is therefore of interest to compare, in a brief 
introductory section, the older with the newer teleological views. 
The distinctive feature of Natural Selection as contrasted with 
other attempts to explain the process of Evolution is the part played 
by the struggle for existence. All naturalists in all ages must have 
known something of the operations of “Nature red in tooth and 
claw”; but it was left for this great theory to suggest that vast 
extermination is a necessary condition of progress, and even of main- 
taining the ground already gained. 
Realising that fitness is the outcome of this fierce struggle, thus 
turned to account for the first time, we are sometimes led to associate 
the recognition of adaptation itself too exclusively with Natural 
Selection. Adaptation had been studied with the warmest enthusiasm 
nearly forty years before this great theory was given to the scientific 
world, and it is difficult now to realise the impetus which the works 
of Paley gave to the study of Natural History. That they did inspire 
the naturalists of the early part of the last century is clearly shown in 
the following passages. 
In the year 1824 the Ashmolean Museum at Oxford was intrusted 
to the care of J. S. Duncan of New College. He was succeeded in 
this office by his brother, P. B. Duncan, of the same College, author 
of a History of the Museum, which shows very clearly the influence of 
Paley upon the study of nature, and the dominant position given to 
his teachings: “Happily at this time [1824] a taste for the study of 
1 More Letters of Charles Darwin, Vol. 1. pp. 354, 355. See also the admirable 
account of incidental colours in Descent of Man (2nd edit.), 1874, pp. 261, 262. 
2 See pp. 273, 276. 
