fishermen find particular kinds of fish always on particular ground? How is it that eels migrate in immense bodies? My opinion is, that particular kinds of fish do hold always together, or at all events gather at particular seasons into greater or lesser bodies. No doubt, life among the inhabitants of the sea, if we could know it, is quite as diversified as life on land, where we observe that many kinds of animals colonise—ants, bees, etc. Are the old stories about each kind of fish having a king so absolutely incredible after all? That there are schools of fish is certain; how the great bodies may be divided can only be guessed. Whatever may be the attracting cause, and however powerful the sexual instinct may be among fish, it can scarcely be discussed fully in a work which makes no pretension to being scientific or even technological. It is noteworthy, however, that fish-eggs afford us an admirable opportunity of studying a peculiarly interesting stage of animal life—viz. the embryo stage—which naturally enough is rather obscure in all animals. Having had opportunities of observing the eggs of the salmon in all their stages of progress, from the period of their first contact with the milt till the bursting of the egg and the coming forth of the tiny fish, I will venture briefly to describe what I have seen, because salmon eggs are of a convenient size for continued examination. The roe of this fine fish is, I daresay, pretty familiar to most of my readers. The microscope reveals the eggs of the salmon as being more oval than round, although they appear quite round to the naked eye. A yolk seems to float in the dim-looking mass, and the skin or shell appears full of minute holes, while there is an appearance of a kind of canal or funnel, which opens from the outside and is apparently closed at the inner end. The milt is found to swarm with a species of very small creatures with big heads and long tails, apparently of very low organisation. On the contact of this fluid with the egg, into which it enters by the canal I have described, an immediate change takes place—the ovum, so to speak, becomes illuminated as if by some curious internal power, and the aspect of the egg then appears a great deal brighter and clearer than before; and it is surely wonderful that on the mere touching of the egg with this wonder-working sperm so great a change should take place—a change which indicates that the grand process of reproduction characteristic of all living nature has begun in the ovum, and will go on with increasing strength to maturity.