The duck is very prolific, and its egg is very much relished by some, having a rich piquancy of flavor, which gives it a decided superiority over the egg of the domestic fowl; and these qualities render it much in request with the pastry-cook and confectioner--three duck's eggs being equal in culinary value to six hen's eggs. The duck does not lay during the day, but generally in the night; exceptions, regulated by circumstances, will, of course, occasionally occur. While laying, it requires, as has been intimated, more attention than does the hen, until it is accustomed to resort to a regular nest for depositing its eggs; when, however, this is once effected, little care is needed beyond what has been indicated. The duck is a bad hatcher, being too fond of the water, and, consequently, too apt to allow her eggs to get cold; she will also, no matter what kind of weather it may be, bring the ducklings to the water the moment they break the shell--a practice always injurious, and frequently fatal; hence the very common practice of setting duck's eggs under hens. There are several _varieties_ of tame ducks; but their merits are more diverse in an ornamental than in a profitable point of view. Of _white_ ducks, the best is the _Aylesbury_, with its unspotted, snowy plumage, and yellow legs and feet. It is large and excellent for the table, but not larger or better than several others. They are assiduous mothers and nurses, especially after the experience of two or three seasons. A much smaller race of white ducks is imported from Holland, useful only to the proprietors of extensive or secluded waters, as enticers of passing wild birds to alight and join their society. This variety has a yellow-orange bill; that of the Aylesbury should be flesh-colored. There is, also, the _white hook-billed_ duck, with a bill monstrously curved downward--a Roman-nosed duck, in fact--with Jewish features, of a most grotesque and ludicrous appearance; the bill has some resemblance in its curvature to that of the Flamingo. White ducks, of course, make but a sorry figure in towns or dirty suburbs, or in any place where the means of washing themselves are scanty. There are one or two pretty varieties, not very common; one of a _slate-gray_, or bluish dun, another of a _sandy-yellow_; there are also some with top-knots as compact and spherical as those of any Polish fowl, which rival the hook-billed in oddity. What are termed the _white_ Poland and the _black_ Poland are crested; they breed early, and are excellent layers; the former are deemed the most desirable though the black are the larger.