The author of this paper had formerly made experiments on the growth of the salmon fry, by procuring spawn from the river bed where it had been deposited by the salmon. Not considering these experiments, however, as entirely unobjectionable, he procured two fishes from the river Nith in the act of spawning; and having expressed the ova of the female in a convenient place, the milt of the male fish was made to impregnate them as nearly as possible in imitation of the natural process. The ova were then placed in ponds prepared for the purpose, and so arranged as to exclude all chances of error as to the species, or the nature of the progeny. The ponds were two in number;—one twenty-five by eighteen feet,—the other fifty by thirty feet, and two feet deep. The bottom was thickly imbedded with gravel, and a small stream of springwater entered the ponds at the upper corner, and escaped by openings at the other end.