Not only can crows and rooks assemble, hold council and agree to act on the result of their deliberations, but other birds are known to do the same things. Birds are able to communicate their thoughts to each other by means of a language, but it is not likely that in their language, or the language of animals in general, there are any principles of construction such as are possessed by all human languages. But the same effect may be produced by different means, and the reader will see that in the above instance no human language, however perfect its construction, could have served its purpose better than did the inarticulate language of the sparrows. They told their friends that their territory was usurped by an intruder too strong to be ejected by them, and implored their assistance. But while it told them this, it did still more, for it conveyed the report to their numerous foes, who winged their way to the support of their opponents. In fact, whenever animals of any kind form alliances and act simultaneously for one common purpose, it is evident that language of some sort must be employed. That beasts possess a language, which enables them to communicate their ideas to each other, has been clearly shown. It is just as apparent that they can act upon the ideas so conveyed. We have now to see whether they can convey their ideas to man, and so bridge over the gulf between the higher and the lower beings. Were there no means of communicating ideas between man and animals, domestication, it is true, would be impossible. Every one who has possessed and cared for some favorite animal must have observed that they can do so. Their own language becomes in many instances intelligible to man. Just as a child, that is unable to pronounce words, can express its meaning by intimation, so a dog can do the same by its different modes of barking. There is the bark of joy or welcome, when the animal sees its master, or anticipates a walk with him; the furious bark of anger, if the dog suspects that anyone is likely to injure himself or his master, and the bark of terror when the dog is suddenly frightened at something which it cannot understand. Supposing, now, that its master could not see the dog, but could only hear its bark, would he not know perfectly well the ideas which were passing through the animal’s mind? Most certainly he would. There is a difference between the mew of distress and the ordinary conversation, the purr of pleasure, of a cat. A pet canary always knows how to call its mistress, and when it sees her will give a glad chirrup of recognition quite distinct from its ordinary call. Bees and wasps have quite a different sound in their wings when angry than when in the discharge of their ordinary work. Any one conversant with their ways understands the expression of anger and makes the best of his way off.