392 THE ZOOLOGIST. 
of British Guiana, states that ‘‘the purple tints on the throat, 
breast, and body of Cotinga cayana, C. cerulea, and Xipholena 
pompadora can be changed to a brilliant red by exposing them to 
heat in such a way as to affect those feathers without singeing— 
an indication of the possibilities in nature under changing 
thermal conditions.’* Where everything is of one assimilative 
hue, such universal protection—if it were such—would rather 
tend to neutralization in all such properties, and other qualities 
would be necessary in the struggle for existence, the absence of 
which might mean starvation and extermination to many species, 
or vice versd—the correlative undue multiplication of others; 
facts which certainly do not appear on the surface. An American 
writer in studying the same problem has given a similar opinion. 
As he observes, ‘its tendency is to bring the colours of the 
animals to agree with those of its surroundings; for this reason 
it has been classed as protective colouration, notwithstanding the 
fact of its occurrence on all the species of a locality whether in 
need of protection or not.” + The very essence of the theory of 
protective resemblance, as a means of survival consequent upon 
the slow but sure action of natural selection, is a special, not a 
general effect,—a particular, not an universal attribute,—but one 
of the many and diverse qualifications which enable animals and 
plants to survive in the competitive struggle for existence. If 
such a suggestion is reasonable or probable, we ought at least to 
find some supportive facts, and these can be gathered, though 
scantily, for the observations of travellers and naturalists do not 
appear to have been greatly attracted in that quarter.[ M. 
* Papers, ‘‘ World’s Congress on Ornithology,” Chicago, p. 124. 
+ Garman, ‘Proc. Am. Ass. Buffalo, N.Y.’ 1876, p. 200. 
t We must, however, carefully guard against hasty or erroneous ob- 
servations. Thus the early South African traveller, Le Vaillant, was told of 
a race of red Elephants, which he afterwards observed were of the same tint 
as the soil on which they were found. But after killing one he proved his 
surmise, that the colour was only due to their wallowing in moist and marshy 
places (‘ Travels in the Years 1780-85,’ Eng. transl. vol. i. p. 266). Again, 
Von Hohnel deseribes the hairless bodies of old male Buffaloes in East Africa 
as being of ‘‘ the colour of the mud—black, grey, brown, or reddish brown, as 
the case may be—in which they last wallowed”’ (‘ Discovery of Lakes Rudolf 
and Stefanie,’ Eng. transl. vol. ii. p. 21). Chanler has a similar observation 
as to a “fred” Rhinoceros (‘ Through Jungle and Desert, p. 120). 
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