"Man favours wonders;" and this delight is almost endlessly exemplified in the stories of strange Fishes--of preternatural size and odd forms, which are to be found in their early history. In our present Talk we do not aim at re-assembling these olden tales, but propose rather to glance at recent accessions to our acquaintance with the study of Fish-life, and a few modern instances of the class of wonders. Fishes, like all other animals, have a very delicate sense of the equilibrial position of their bodies. They endeavour to counteract all change in their position by means of movements partly voluntary and partly instinctive. These latter appear in a very remarkable manner in the eye; and they are so constant and evident in fishes while alive, that their absence is sufficient to indicate the death of the animal. The equilibrium of the fish, its horizontal position, with the back upwards, depends solely on the action of the fins, and principally that of the vertical fins. The swimming-bladder may enable a fish to increase or diminish its specific gravity. By compressing the air contained in it, the fish descends in the water; it rises by releasing the muscles which produced the compression. By compressing more or less the posterior or anterior portion of the bladder, the animal, at pleasure, can make the anterior or posterior half of its body lighter; it can also assume an oblique position, which permits an ascending or descending movement in the water. There is a small fish found in the rivers of the Burmese Empire, which, on being taken out of the water, has the power of blowing itself up to the shape of a small round ball, but its original shape is resumed as soon as it is returned to the river. Mr. St. John, in his "Tour in Eastern Lanarkshire," gives some curious instances of fish changing colour, which takes place with surprising rapidity. Put a living black burn Trout into a white basin of water, and it becomes, within half an hour, of a light colour. Keep the fish living in a white jar for some days, and it becomes absolutely white; but put it into a dark-coloured or black vessel, and although on first being placed there the white-coloured fish shows most conspicuously on the black ground, in a quarter of an hour it becomes as dark-coloured as the bottom of the jar, and consequently difficult to be seen. No doubt this facility of adapting its colour to the bottom of the water in which it lives, is of the greatest service to the fish in protecting it from its numerous enemies. All anglers must have observed, that in every stream the Trout are very much of the same colour as the gravel or sand on which they live: whether this change of colour is a voluntary or involuntary act on the part of the fish, the scientific must determine.