274 Colour and the Struggle for Life 



wild animals 1 ." Burchell here seems to miss, at least in part, the 

 meaning of the relationship between the quiescence of the Acridian 

 and its cryptic colouring. Quiescence is an essential element in the 

 protective resemblance to a stone probably even more indispensable 

 than the details of the form and colouring. Although Burchell 

 appears to overlook this point he fully recognised the community 

 between protection by concealment and more aggressive modes of 

 defence ; for, in the passage of which a part is quoted above, he 

 specially refers to some earlier remarks on p. 226 of his Vol. I. We 

 here find that when the oxen were resting by the Juk rivier (Yoke 

 river), on July 19, 1811, Burchell observed "Geranium spinosum, with 

 a fleshy stem and large white flowers. . . ; and a succulent species of 

 Pelargonium... so defended by the old panicles, grown to hard woody 

 thorns, that no cattle could browze upon it." He goes on to say, " In 

 this arid country, where every juicy vegetable would soon be eaten 

 up by the wild animals, the Great Creating Power, with all-provident 

 wisdom, has given to such plants either an acrid or poisonous juice, 

 or sharp thorns, to preserve the species from annihilation...." All 

 these modes of defence, especially adapted to a desert environment, 

 have since been generally recognised, and it is very interesting to 

 place beside Burchell's statement the following passage from a letter 

 written by Darwin, Aug. 7, 1868, to G. H. Lewes: "That Natural 

 Selection would tend to produce the most formidable thorns will be 

 admitted by every one who has observed the distribution in South 

 America and Africa (vide Livingstone) of thorn-bearing plants, for 

 they always appear where the bushes grow isolated and are exposed 

 to the attacks of mammals. Even in England it has been noticed 

 that all spine-bearing and sting-bearing plants are palatable to 

 quadrupeds, when the thorns are crushed 2 ." 



Adaptation and Natural Selection. 



1 have preferred to show the influence of the older teleology upon 

 Natural History by quotations from a single great and insufficiently 

 appreciated naturalist. It might have been seen equally well in the 

 pages of Kirby and Spence and those of many other writers. If the 



1 Loc. cit. pp. 310, 311. See Sir William Thiselton-Dyer "Morphological Notes," xi.; 

 ''Protective Adaptations," i. ; Annals of Botany, Vol. xx. p. 124. In plates vn. viu. and 

 ix. accompanying this article the author represents the species observed by Burchell, 

 together with others in which analogous adaptations exist. He writes: " Burchell was 

 clearly on the track on which Darwin reached the goal. But the time had not come for 

 emancipation from the old teleology. This, however, in 110 respect detracts from the merit 

 or value of his work. For, as Huxley has pointed out (Life and Letters of Thomas Henry 

 Huxley, London, 1900, i. p. 457), the facts of the old teleology are immediately transferable 

 to Darwinism, which simply supplies them with a natural in place of a supernatural 

 explanation." 



- More Letters, I. p. 308. 



