place between them. Pierquin adds that baffled love often leads man as well as animals into a murderous monomania. Buffon cites examples of animals which were frequently subject to a murderous passion. He speaks of canary-birds which were so wicked as to kill the female that was given them, and which could not be broken of the practice except by giving them two. Others are so barbarous in their inclinations as to break and eat the eggs as soon as they have been laid; and, even if the unnatural father allows the eggs to be sat upon, he will kill the young as soon as they are hatched. Pierquin mentions cross, quarrelsome dogs that are always ready to fight upon the smallest provocation. Wickedness of this kind may be manifested in certain races; it may be individual, permanent, and hereditary; or, while it is still individual, it may be accidental and transient, provoked by particular circumstances.
We may call a specific malignity that which one species shows toward another species that hunts it or is its rival in the struggle for existence. The instinctive repulsion of dogs and cats is proverbial. It is interesting, however, to observe how this repugnance can cease under certain conditions, as when the struggle for existence becomes less active. Commander Mouchez asserts that the cats and the rats on the Island of St. Paul, where he went to observe the transit of Venus, have ceased to war upon each other, and have instead joined in hunting birds. Cases of permanent and hereditary maliciousness are not rare. All who have had to do with domestic animals, says M. Cornevin, have observed that there appear among our subdued species, horses and cattle, individuals, both male and female, which are intractable, vicious, and absolutely useless; just as individuals of a similar character sometimes appear in human society. Such traits are often hereditary.
We have examples of the excitation of the destructive propensity by higher faculties in which malice seems to be consecutive to a real reasoning. First among them is the case of malice aroused by the recollection of bad treatment. Animals with such passion become murderers for revenge. They say that the mule always keeps a kick in store for the master who maltreats it; and examples are frequent of asses, mules, and horses, that were very gentle till they were chastised, remembering the blows they had received, and avenging themselves on the drivers who inflicted them. There are also murderers for rivalry. A bull that has been gentle enough as long as he has had his cows to himself will become vicious as soon as a rival is brought into the field, and will try to kill him or drive him away, and always keep watch over him.
M. Colin, in his treatise on the "Physiology of the Domestic Animals," cites two curious examples of criminality developed under the operation of the nutritive instinct. A dog at the school of Alfort, which was fed on the remains of dissected bodies, conceived a violent