From the middle of December to the end of January the Trout is in full spawning operation; when the fish deposit their eggs in the hollow, and afterwards work the gravel over them to the depth of about three inches. If the temperature of the water is not altered during the period of incubation, the young make their appearance on the fiftieth day; never earlier, frequently later. Nature has endowed the young fry with so much instinct of self-preservation, that for many days they keep under the gravel, and it is curious to see the shoal hiding together under large stones to protect themselves from danger: this they continue to do until the eggshell, in which they remain partially enveloped, falls off from their delicate frames. This shell, which adheres to them for fourteen days, contains a proportion of fluid necessary for their support during this period of helplessness. After this they resort to the shallows and scours to avoid the larger fish, where they remain solitary for a year, during which time, in good keep, they attain the weight of three to four ounces; the second year, eight to ten ounces; after which they begin to breed. A fish, like every animal, becomes fat when it has abundance of food with little or no exertion; so that the growth is entirely regulated by the relative proportion of food and labour. I have observed this difference in the same brood of Trout, artificially bred upon my system: the one brood being placed in water well supplied with food, the other in a spring-stream where little food existed; the former, at ten months old, were four inches long, and three and a half ounces in weight, while the latter were only an inch and a half long, and less than an ounce in weight. Although Trout are not migratory, yet, when they become large, they run up stream to purer water. The small Trout are carried down the stream against their habit, by the flushes of water or floods during the autumn months, being unable to stem the thickened torrent, which fills their gills with alluvial deposit, and hinders their respiration, whence they become weak and sickly. In this state of water all fish sicken more or less, and it destroys vast numbers in the very young state. I have known thousands destroyed by the overflowing of a river, as well old as young. The cause of all our rivers falling off in the quantity of fish, is from the increasing impurity of the water, as fish especially require pure water. _The above interesting notice of the Trout has been communicated to the publisher by_ MR. BOCCIUS, _who devotes himself professionally to the increase of fish in rivers and ponds, and has performed marvels._ [Illustration: THE CHAR, OR ALPINE TROUT, (_Salmo salvelinus_,)]