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woodpecker, “ Can a more striking instance of adaptation be given 
than that of a woodpecker for climbing trees, and for seizing insects 
in the chinks of the bark? Yet in North America there are wood- 
peckers which feed largely on fruit, and others with elongated wings 
which chase insects on the wing ; and on the plains of La Plata, 
where not a tree grows, there is a woodpecker, which in every essen- 
tial part of its organisation , even in its colouring, in the harsh tone 
of its voice, and undulatory flight, told me plainly of its close blood 
relationship to our common species ; yet it is a woodpecker which 
never climbs a tree.” (P. 184.) I have selected this instance both as 
a statement bearing upon the effect of physical condition which appears 
to me to require correction, and also as an illustration of the neces- 
sity, in such an investigation as this, of testing every fact before ad- 
mitting it. This is a statement made upon Mr Darwin’s own personal 
observation, confirming that of Azara. I do not believe there is a 
more upright and truthful man in Britain than Mr Darwin, and yet 
we look at things from such an opposite point of view, that I not 
only do not see what he avers in the above instance, but see quite 
the reverse. The woodpeckers he refers to are Colaptes (the La 
Plata species is, I believe, the Colaptes campestris ) ; and so far 
from appearing to me to possess every essential point of the organi- 
sation of a woodpecker, they are one of the very instances which I 
have been in use to give as showing the alteration of structure in a 
type consequent upon different physical conditions of life. The 
Colaptes, although allied to the woodpeckers, differ from them in 
mode of life, inasmuch as they feed upon ants ; and, in structure, 
inasmuch as not requiring that most essential part of the organisa- 
tion of a woodpecker (its peculiar hammering bill and strong tail) 
they do not possess them, while they retain the peculiar tongue and 
accessory muscles still necessary for securing their insect food. 
The strongest points in favour of the general results come to by 
Mr Darwin, are a class of facts which can scarcely be said to bear 
distinctively on his theory more than upon various other theories 
already promulgated, and more or less adopted. One of these is the 
fact, that all animals, and all plants, throughout all time and space, 
should be related to each other in group subordinate to group. 
Another not less formidable fact is the existence of the same homo- 
logical parts in different animals, sometimes aborted, and sometimes 
largely developed. 
