27 



ful nftcr oxidation to the growing- crop. In the gr >\vth of leguminous 

 plants, as has already been intimated, another important supply of 

 organic nitrogen may be secured, some of which, at least, is a clear, 

 gain from the atmosphere. Other important forms of nitrogenous 

 materials are found in the pressed cakes left after the extraction of the 

 oil from oil-producing seeds, such as flax and cotton seed. These cakes 

 are exceptionally rich in nitrogenous matter which may be secured for 

 the field both by the direct application of the ground material to the 

 soil, or by first feeding it to animals, the part which escapes digestion 

 in the latter case being still a valuable fertilising material In the case 

 of cotton-seed cake, moreover, it should not be forgotten that there is 

 some danger in feeding it, especially to young cattle, on account of the 

 poisonous nitrogenous bases (cholin and betain) which it contains. 



These poisonous bases produce no deleterious effects whatever in the 

 soil, although it is doubtful whether they are attacked very readily by 

 the nitrifying ferments. Other sources of nitrogenous foods for the soil 

 ferments are found in the refuse of slaughter houses. Dried blood is 

 perhaps the richest in nitrogen of any organic substance that is known, 

 and is readily attacked by the soil ferments. The nitrogenous refuse of 

 slaughtered animals, after the extraction of the fat, is dried and ground 

 and sold under the name of tankage. It is a substance very rich in 

 nitrogenous matter. The bones of animals are not only valuable on 

 account of the phosphoric acid which they contain, but also have a large 

 percentage of nitrogenous material which renders them particularly well 

 suited for application to a soil deficient both in phosphoric acid and 

 nitrogen. For this reason, burning bones before grinding them for fer- 

 tilising purposes, which is done in some localities, is extremely wasteful. 

 For a similar reason, also, the composting of coarsely ground fresh bones 

 with wood ashes is not to be recommended, because of the tendency of 

 the alkali of the ashes to set free, in the form of ammonia, at least a part 

 •f the nitrogenous content of the bones. 



CONTRIBUTIONS FROM THE OCEAif 



The farmer, happily, is not confined alone to the land for the sources of 

 organicnitrogen with which to supply the demands of the nitrifying fer- 

 ments of his field. The ocean is made to contribute to the stores of 

 nitrogenous matters to which the farmer has acccess. The vast quantities 

 of seaweed which are thrown up annually upon our shores are rich in 

 nitrogenous matters. The value of this material, however, is not 

 generally appreciated, but in some parts of the country it is carefully 

 gathered and utilised. The value of this product gathered annually upon 

 the shores of Rhode Island alone is nearly 100,000 dols. While seaweed, 

 for obvious reasons, can only be successfully applied in marine literal 

 agriculture, yet the extent of agricultural lands bordering on the sea is so 

 great as to render the commercial importance of the matter of the 

 highest degree of interest. Seaweed is not valuable for its nitrogenous 

 constituents alone, but also carries large quantities of potash and phos- 

 phoric acid, and thus to a certain degree, it may be regarded as a com- 

 plete fertiliser. But the seaweed which is thrown upon our shores is not 

 the only source of nitrogenous food which we receive from the ocean. In 

 the animal life of the ocean are gathered vast quantities of nitrogenous 

 materials. The quantity of albuminoid matter in the water-free sub- 



