HARDWICKKS SCIENCE-GOSSIP. 



73 



ON ANIMAL BEAUTY. 



By Dr. P. Q. KEEGAN. 



[Continued from p. 64.] 



N the next place, the 

 beauty of colour in 

 animals claims our 

 attention. The 



beauty of form is, 

 as we have seen, 

 referable to the in- 

 ternal skeleton, the 

 muscular and fatty 

 tissue ; but it would 

 appear that the 

 blood, the skin, 

 and the liver are 

 principally con- 

 cerned in the pro- 

 duction of organic 

 tint and hue. This 

 species of beauty 

 is in its effect more 

 sensuous and less 

 "intellectual, "than 

 the beauty of form. Nothing can exceed the loveliness, 

 the gorgeous colouring of the humming-birds, the 

 sun-birds, many fishes, the trogons, Buprestidse, etc. 

 Iridescence produced by the fibres, and the deposition 

 from the blood of distinct pigments, are the two 

 immediate sources of animal colours. The chemical 

 constituents of the blood, its activity and richness, 

 and above all the oxygen with which it is saturated, 

 contribute to their production ; and frequently the 

 transparency of the tissues imparts thereto a fairy-like 

 aspect which is inexpressibly charming . In discussing 

 the subject of form we have observed how it is that 

 to every animal configuration there is set, as it were, 

 an ideal exemplar or model which it more or less 

 embodies according as it exhibits more or less of 

 beauty. In the species of beauty we are now review- 

 ing, the necessity of such an ideal is not so patent, 

 nor does there appear therein such an obvious de- 

 velopment of force or such a thorough elaboration of 

 structure. When we see a hideous or loathsome 

 shape we recognise some defect of harmony or of 

 No. 256.— April 1886. 



congruity ; when we see a pale or repulsive colour, 

 we judge it to be deficient in itself and as of itself. 

 Another feature worthy of notice is that, once an 

 animal is made, its stamp of form and contour is 

 generally preserved throughout its life ; whereas its 

 colouring is frequently subject to periodical change. 



This periodical change of colour is observable 

 especially amongst birds. It is known that a change 

 takes place in the plumage of all birds at the beginning 

 of the breeding season. The pigment cells of the 

 feathers, etc., either increase in number, or, if already 

 developed, become expanded. These lovely creatures 

 are never more lovely than in the spring-time, when 

 their apparel changes in a wonderful manner from the 

 sombre shades of the winter to colours and tints the 

 most gorgeous. And this is the very season when 

 their life-energy is most potent and actively elevated ; 

 when, almost perpetually on the wing, they flit 

 restlessly from branch to branch, or make the 

 woodlands echo with their songs, or vigorously 

 engage in the active duties of parentage. Fishes, 

 too, at the breeding season assume lovely colours, 

 and roam in shoals over the waters, or pertinaciously 

 advance up rivers. In the case of insects it is seen 

 that so long as they remain in the dull and lifeless 

 larva and pupa states they are comparatively un- 

 attractive ; but, once they assume the imago or perfect 

 condition, they become active and beautiful. The 

 beetle tribe, which haunts and moves slowly about 

 the ground and rarely takes wing, is not very lovely; 

 but the remarkably active and practically energetic 

 bee, dragon-fly, and butterfly, etc., are among the 

 most gorgeously apparelled of animals. All this 

 periodical or seasonable change or modification of 

 colour would seem to indicate that animal beauty in 

 this particular arises not from any of the more solid 

 and permanent constituents of the organism, but rather 

 from some (such as the blood) which is subject to 

 great variation in respect to its quantity or quality or 

 to (the most efficient of all) what we may style its 

 vitalising property. Animal pigment consists of 

 granules usually enclosed in cells, and these cells 



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