_Guano_ as a manure has become world renowned. The worn-out tobacco lands of Virginia, and other fields in many parts of the country, which seemed to have yielded to the effect of an ignorant course of cultivation, and to have sunk to their final repose, have in many cases been revived to the production of excellent crops, and have had their value multiplied many fold by the use of guano. Although an excellent manure, it should not cause us to lose sight of those valuable materials which exist on almost every farm. Every ton of guano imported into the United States is an addition to our national wealth, but every ton of stable-manure, or poultry-dung, or night soil evaporated or carried away in rivers, is equally a _deduction_ from our riches. If the imported manure is to really benefit us, we must not allow it to occasion the neglect and consequent loss of our domestic fertilizers. The Peruvian guano (which is considered the best) is brought from islands near the coast of Peru. The birds which frequent these islands live almost entirely on fish, and drop their excrements here in a climate where rain is almost unknown, and where, from the dryness of the air, there is but little loss sustained by the manure. It is brought to this country in large quantities, and is an excellent fertilizer, superior even to night soil. [How should it be prepared for use?] It should be mixed with an absorbent before being used, unless it is plowed deeply under the soil, as it contains much ammonia which would be lost from evaporation. It would probably also injure plants. The best way to use guano, is in connection with sulphuric acid and bones, as will be described hereafter. The composition of the various kinds of guano may be found in the section on analysis. FOOTNOTES: [AA] The nitrogenous compound in the urine. [AB] Comparatively. CHAPTER VII. OTHER ORGANIC MANURES. The number of organic manures is almost countless. The most common of these have been described in the previous chapters on the excrements of animals. The more prominent of the remaining ones will now be considered. As a universal rule, it may be stated that all organic matter (every thing which has had vegetable or animal life) is capable of fertilizing plants. DEAD ANIMALS. [What are the chief fertilizing constituents of dead animals? What becomes of these when exposed to the atmosphere? How may this be prevented?] The bodies of animals contain much _nitrogen_, as well as valuable quantities, the phosphates and other inorganic materials required in the growth of plants. On their decay, the nitrogen is resolved into _ammonia_,[AC] and the mineral matters become valuable as food for the inorganic parts of plants.