246 MR J. B. DOBBIE ON 
circumstance such analogy should in any way or to any 
extent add to the knowledge which aids us in the determina- 
tion of the permanent qualities of genera and species, it is 
a mere truism to say that the subject has the highest claims 
to careful scientific observation. There is a reason for every 
irregularity ; and it is indubitable that the beautiful and fan- 
tastic variegations which frequently adorn the shells of eggs. 
depend on some cause or series of causes as yet unexplained. 
Hewitson, whom we have already quoted, considers that such 
decoration has no direct function in the economy of Nature, 
and that it is only an accidental property designed by a 
beneficent Creator for the purpose of gladdening and beauti- 
fying the earth. 
“ The beauties of the wilderness are His, 
That makes so gay the solitary place, 
Where no eye sees them.” 
There they are! “ born to blush unseen” till man finds. 
access to their remote and neglected habitat. By the orthodox 
savants of the past no further explanation was thought 
necessary ; but the Darwinian naturalists are not so easily 
satisfied, and to them the phenomena of colour in the organic 
world has been the subject of much speculation. It is the 
business of the chemist and of the physicist to investigate 
the principles upon which the law of refraction and reflec- 
tion, and the general photographic action of light, come to: 
exert an influence upon the adaptive parts of an animal 
system ; it is the business of the physiologist to examine the 
relations which may exist between the action and the modi- 
fications or changes to which such organisms may be liable. 
An intimate connection between light and colour there cer- 
tainly is, and the great exuberance of life in the Tropics has 
led many to accept the theory that colour is wholly dependent 
upon the influence of the solar rays. Thus Mr Ruskin, with 
all the vividness of his beautifully poetic mind, has pictured 
the gradual decrease of colouring in Nature when viewed in 
proportion to its distance from the Torrid Zone. “ Such,” 
according to him, “ would be the aspect of the earth if, rising 
higher than the Stork or the Swallow as they lean upon the 
wind, we could gaze down upon the variegated mosaic of 
