As the oyster will not grow on all kinds of bottom, but demands a firm soil, free from soft mud and shifting sand, the oyster area of the State is naturally limited. Usually but part of an oysterman's grant is suitable for the cultivation of oysters, and he is forced to let the rest of the territory lie idle, unless he can, with shells or gravel, artificially change this waste area into suitable ground. Shifting sand perhaps can never be made suitable for oysters; but many acres of soft mud can be made productive, if the oysterman only has a reasonable guarantee that he would receive the results of his labor. While the oyster culture is limited by the nature of the bottom, it is also restricted by other conditions. The salinity of the water has much to do with the rapidity of growth, and the oysters seem to thrive in localities where a slight amount of fresh water enters. The amount of food in the water is the principal factor in the rate of growth, and to this is due the fact that the rate of growth varies considerably in different localities. As a rule, the beds with good circulation of water (_i.e._, currents) show the more rapid growth. II. _Collecting the "Seed."_--The term "seed" is applied to one, two, three and even four year old oysters which the oystermen plant on their grants. These grants are in reality salt-water gardens, requiring constant supervision; and the obtaining of the "seed" for planting is a most important consideration. The gathering of the oyster "seed" is a simple process, but one which requires much research. Early in the summer, usually during the months of June and July in these waters, the Massachusetts oyster spawns. Both sperm from the adult male and the eggs from the adult female oysters are extruded in considerable quantities into the water, and there the eggs are fertilized. As fertilization is somewhat a matter of accident, undoubtedly the great majority of eggs never develop. The fertilized eggs pass rapidly through various changes in the course of a few hours, and emerge as microscopic embryos, with thin, transparent coverings. At this period these forms are free swimming, and are found in great numbers in the water. They are extremely delicate, and great quantities are destroyed by natural agencies, such as cold storms, sudden changes in temperature, etc. They likewise are subject to the depredations of all sorts of marine creatures, and comparatively few in proportion survive. The survivors, after leading this free-swimming existence for several days, settle to the bottom, where they attach themselves by a calcareous fixative to stones, shells, pieces of wood, etc. Here, unless buried by silt and soft mud or killed by exposure, poisonous pollution, etc., the young oyster rapidly becomes of a size suitable for planting.