The countenance may, occasionally, be observed lighted up, as it were, from within by a passing dream--its expression is frequently one of peculiar mildness and benignity; the breathing may be slow, but it is calm and uniform: the pulse not so rapid as in the waking state, but soft and regular; the composure of the whole body may continue trance-like and perfect. There is, indeed, no sign of innocence more touching than the smile of a sleeping infant. But, suddenly, this state of tranquillity may be disturbed; the dreamer changes his position and become restless; he moans grievously--perhaps sobs--and tears may be observed glimmering underneath his eyelids; his whole body now seems to be shaken by some inward convulsion; but, presently, the strife abates; the storm-cloud gradually passes; he stretches his limbs, opens his eyes, and, as he awakes, daylight, in an instant, dispels the vision, perhaps leaving not behind the faintest trace or recollection of a single incident which occurred in this mysterious state. But what are dreams? Whence come they? What do they portend? Not man only, but all animals, it is presumed, dream, more or less, when they are asleep. Horses neigh, and sometimes kick violently; cows, when suckling their young calves, often utter piteous lowings; dogs bark in suppressed tones, and, from the motions of their paws, appear to fancy themselves in the field of the chase; even frogs, particularly during summer, croak loudly and discordantly until midnight, and then retire, and become silent. Birds also dream; and will sometimes, when frightened, fall from their roosting-perch, or flutter about their cage, in evident alarm. A bullfinch, says Bechstein, belonging to a lady, was subject to very frightful dreams, which made it drop off its perch; but no sooner did it hear the voice of its affectionate mistress than it became immediately tranquil, and reascended its perch to sleep again. It is pretty certain that parrots dream. It is, indeed, a curious circumstance that the best way of teaching this bird to talk is to cover the cage over so as to darken it, and while he is going to sleep pronounce, audibly and slowly, the word he is to learn; if the winged pupil be a clever one, he will, upon the repetition of the lesson, in a morning or two, begin to repeat it.