of Edinburgh, Session 1864-65. 283 
of the “ Comets,” in which two different kinds of luminous reds or 
crimsons are nearly all that serve to distinguish the species. 
A similar principle of variation applies in other genera, where 
the amount of difference is greater. For example, one of the most 
singular and beautiful of all the tribe is comprised within the 
genus Lophornis,” or the “ Coquettes.” The principle of orna- 
ment in this genus is, that the different species are all provided 
both with brilliant crests, and with frills or tippets on the neck. 
The feathers of these parts are generally of one colour, ending in 
spots or spangles of another; the spangles being generally of 
metallic lustre. There seems to be a rule of inverse proportion 
between the two kinds of ornament. The species which have the 
neck plumes longest have the shortest crests, and vice versa. In 
the shape and structure of all essential organs there is hardly any 
difference between the species. T need not multiply instances 
farther, since many others of the same kind will be observed in Mr 
Grould’s splendid work. Now, what explanation does the law of 
natural selection give — I will not say of the origin, but even of the 
continuance and preservation — of such specific varieties as these ? 
None whatever. A crest of topaz is no better in the struggle for 
existenee than a crest of sapphire. A frill ending in spangles of 
the emerald is no better in the battle of life than a frill ending in 
spangles of the ruby. It is impossible to bring such varieties into 
relation with any physical law known to us. It has relation, how- 
ever, to a purpose, which stands in close analogy with our own 
knowledge of purpose in the works of man. Mere beauty and mere 
variety, for their own sake, are objects which we ourselves seek 
when we can make the forces of nature subordinate to the attain- 
ment of them. There seems to be no conceivable reason why we 
should doubt or question, that these are ends and aims also in the 
forms given to living organisms, when the facts correspond with 
this view, and with no other. In this sense, wo can trace a crea- 
tive law, — that is, we can see that these forms of life do fulfil a pur- 
pose and intention, which we can appreciate and understand. 
But then it may be asked, has this purpose and intention been 
attained without the use of means? Have no physical laws been used, 
whereby these new forms of beauty have been evolved, the one 
from the other, in a series so wonderful for its variety in unity, and 
