146 THE HISTORY OF CREATION. 
exists this difference, that the former are capable of pro- 
ducing fruitful bastards, but that the latter are not. Two 
different cultivated races, or wild varieties of one species, 
are said in all cases to possess the power of producing 
bastards which can fruitfully mix with one another, or 
with one of their parent forms, and thus propagate them- 
selves; on the other hand, two really different species, two 
cultivated or wild species of one genus, are said never to be 
able to produce from one another bastards which can be 
fruitfully crossed with one another, or with one of their 
parent species. 
As regards the first of these assertions, it is simply re- 
futed by the fact that there are organisms which do not 
mix at all with their own ancestors, and therefore can 
produce no fruitful descendants. Thus, for example, our 
cultivated guinea-pig does not bear with its wild Brazilian 
ancestor ; and again, the domestic cat of Paraguay, which is 
descended from our European domestic cat, no longer bears 
with the latter. Between different races of our domestic 
dogs, for example, between the large Newfoundland dogs 
and the dwarfed lap-dogs, breeding is impossible, even for 
simple mechanical reasons. A particularly interesting in- 
stance is afforded by the Porto-Santo rabbit (Lepus Hux- 
leyi). In the year 1419, a few rabbits, born on board 
ship of a tame Spanish rabbit, were put on the island of 
Porto Santo, near Madeira. These little animals, there 
being no beasts of prey, in a short time increased so enor- 
mously that they became a pest to the country, and even 
compelled a colony to remove from the island. They still 
inhabit the island in great numbers; but in the course of 
four hundred and fifty years they have developed into a quite 
