When I see the several actions and designs of my Dog, I profess it is impossible to avoid being amazed. His passions are more quiet than those of many men. There are some whose joy or grief at accidents, give them so little emotion, and are so dull, as to render it difficult to say which it is that affects them: but, in this honest animal, both are lively and strong. When any of the family return home, he discovers great gladness in caressing and skipping about them, and seems dull and concerned at their going out. But there is one among them whom he distinguishes in a most peculiar manner. When this person goes abroad, he is void of all comfort, and sits in a window crying incessantly, refusing victuals, and watching for his friend's return; who is always welcomed by much rejoicing and noise. If he wants to go out of the room, he puts his fore feet up against one of the company, and being taken notice of, runs to the door, rising up against it in the same manner, looking at the person he gave notice to before, till he be let out. If he wants to drink, he gives the same notice, and immediately runs into a closet, where stands a bottle of water, continuing to run to and from the person till he be served.
Dr. Parson, on Animals and Vegetables -- from The general character of the dog: illustrated by a variety of original and interesting anecdotes of that beautiful and useful animal in prose and verse, Joseph Taylor, ed. (London: Darton and Harvey, 1804), p. 13-14. I think this is the same Dr. Parson referenced (exhaustively!) here.