2993- on varieties of domestic animals 233 
be looked upon, as a great curiosity, it would of 
course be valued—preserved with care—and its de- 
scendants, if bearing marks of the same sort, also pre-~ 
served. A male and female of this kind being onc® 
obtained, this diversified breed would be perpetuated ; 
and these afterwards intermingling with others, would 
destroy the uniformity of appearance of the wild 
breed. Another diversity of colour or appearance, 
being in the same way selected, this also would oce 
casion frefh room for new diversities. By a si- 
milar mode of selection, continued forages, some 
persons fancying one variety, and some another, it. 
must at last happen that the diversities will become 
so numerous, as that the original breed can scarcely 
be distinguifhed from the others. 
Now, although similar accidental diversities of an 
individual, sometimes occur in a state of nature, these, 
for the reasons above afsigned, are quickly lost; 
and the general breed continues unvaried. That 
such diversities sometimes do occur among wild ani- 
‘mals, is well known by every collector of natural 
curiosities. I have myself seen a blackbird, rT. meruda, 
of a milk white colour, that was fhot in a wild state, 
I once saw a rook mottled black and white, exadtly 
like a magpie, among a great flock of others. I have 
seen a tame white mouse ; and a whole nest of young 
mice were once brought to me, consisting of ten or 
twelve, which were either white or mottled, and 
I think few or none of them were entirely of the 
ordinary mouse colour. This I presume had heen 
the progeny of a mouse probably pure white, with a 
mate of the usual colour. If among this nestling, 
VOL. XVile GG 
