these fishes is crude and faulty in the greatest degree. Nor can it be said that this wastefulness is compensated by the great number of eggs, for the production of so many eggs by the mother involves a great expenditure of force, which might be saved by more highly-developed instincts.
In view of all the instances given, I think we may conclude that instinct is not a fixed, immutable, perfect law and guide, but an imperfect, improvable, gradually-acquired method of adjusting actions to the surrounding conditions; and therefore subject to slow perfection through the survival of the fittest variations. Let us now see whether animals possess other mental powers than the instinctive; whether they exhibit any faculty which may properly be called intelligence. No one doubts that most of our domestic animals admit of individual improvement or education, but it may be said that this improvement is due to man's intelligence, not to that of the animals themselves. There is abundant proof, however, that animals are capable of much individual improvement in a state of nature. You can't catch old birds with chaff; and a new trap partakes of the properties of a new broom, Morgan, in his book on "The American Beaver and his Works," says that beaver-houses are often found of a construction very inferior to the average; and that, according to the Indians, these are the work of young animals which have not yet completed their education. Every one who has studied the habits of cats knows how frequently they fail to raise their first litter of kittens, and a very careful observer tells me that this is true of white mice to a much greater degree.
Leroy, a writer of the seventeenth century, and a very reliable authority, says that there is a marked inferiority in the nests made by young birds, and that the best and most complicated nests are made by those species of birds whose young remain a long time in the nest, and thus have more opportunity to see how it is made.
He says that not only are the nests of young birds badly made, but that very unfit places are chosen for them, and that these defects are remedied in time when the builders have been instructed by their sense of the inconvenience they have endured. Wilson likewise claimed that there is a very perceptible inferiority in the nests of young birds. To one at all familiar with animals, the fact that each individual undergoes a process of intellectual development and self-education is so familiar that it seems strange that any one should question it; but, as the contrary statement is still occasionally met with, it seemed proper to give the above instances of improvement.
The fact that dogs dream, and under circumstances of peculiar hardship and misfortune become crazy, seems to indicate a very close similarity between their minds and ours; and no one who has seen an idiotic or half-witted dog can doubt that an ordinary dog has a mind to lose.