The conservation and increase of the stores of available nitrogen in the soil is one of the chief problems occupying the attention of agricultural chemistry. Nitrogen, which is not immediately available for the growth of plants, is conserved and restored by natural processes in various ways. The waste nitrogen finds its way sooner or later to the sea, and is restored therefrom in many forms. Sea-weeds of all kinds are rich in recovered nitrogen. Many years ago Forchhammer[6] pointed out the agricultural value of certain fucoids. Many other chemists have contributed important data in regard to the composition of these bodies. Jenkins[7] has shown from the analyses of several varieties of sea-weeds that in the green state they are quite equal in fertilizing value to stall manure, and are sold at the rate of five cents per bushel. These data are fully corroborated by Goessmann.[8] Wheeler and Hartwell[9] give the fullest and most systematic discussion which has been published of the agricultural value of sea-weeds. Sea-weed was used as a fertilizer as early as the fourth century, and its importance for this purpose has been recognized more and more in modern days, especially since chemical investigations have shown the great value of the food materials contained therein. To show the commercial importance of sea-weed, it is only necessary to call attention to the fact that in 1885 its value as a fertilizer in the State of Rhode Island was $65,044, while the value of all other commercial fertilizers was $164,133. While sea-weed, in a sense, can only be successfully applied to littoral agriculture, yet the extent of agricultural lands bordering on the sea is so great as to render its commercial importance of the highest degree of interest. A large amount of nitrogen is also recovered from the sea in fishes. It is shown by Atwater[10] that the edible part of fishes has an unusually high percentage of protein. In round numbers, about seventy-five per cent of the water free edible parts of fish are composed of albuminoids. Some kinds of fish are taken chiefly for their oil and fertilizing value, as the menhaden. Squanto,[11] an American Indian, first taught the early New England settlers the manurial value of fish.