The growth of a clam depends upon the circulation of water over the flat, as the current carries the food, and, therefore, the more current the more food for the clams. Current also keeps the bed clean, and prevents contamination and disease from spreading among the clams. Then, again, the growth of a clam depends upon the amount of water over the bed; _i.e._, length of time covered. The clam can only feed when the tide is over the bed, and thus the feeding time is limited for the higher flats. While experiments have shown that clams grow faster when continually under water than when exposed part of the time, the question of tide is not so great a factor as that of current in regard to clam growth, and can be almost disregarded. The best flat for clam planting is a _fairly high flat_ with a _good current_ over it, as it gives nearly as rapid growth and a much longer period to dig than a flat which is exposed only a short period. This flat must have the right kind of soil, which must not be shifting sand or too soft mud, but a compact, tenacious mixture. _The Seed Clams._--Nature has provided the means of stocking these farms. The set of clams is usually restricted to certain localities, which, however, vary from time to time, and heavy sets are found in limited areas. These sets run as thick as 2,000 per square foot of surface, occasionally covering an area of 3 acres. From these natural set areas the natural clam flats are partially restocked by the washing out of the small clams. More often these whole sets are wasted, as the clams, instead of washing on the good flats, are carried to unproductive places and consequently perish. Thus there are areas of heavy set which are of no use to any one, as practically all the clams perish before they become adults. These areas of heavy set occur in nearly every harbor of the coast to a greater or less extent, and are available for nearly every town. The problem now is to make use of these large sets, and not allow them to go to waste. It has been shown that these clams when transplanted will grow much faster, and will not perish; therefore, clam farming offers both the possibility of saving these natural sets and utilizing barren ground. Methods of spat collecting have been constantly referred to in connection with clam farming, especially by the Rhode Island Fish Commission, and the impression has been given that clam farming can never become a success until some practical method of spat collecting has been found. With the soft clam there is no need of any method of spat collecting, as the natural set is more than sufficient for restocking the barren flats. All that is necessary is to utilize the enormous natural sets. If this is done, the barren flats of Massachusetts can be made productive.