It is evident that this is the case from the fact that plants have it for their direct object to make over and put together the refuse organic matter, and the gases and the minerals found in nature, for the use of animals. If there were no natural means of rendering the excrement of animals available to plants, the earth must soon be shorn of its fertility, as the elements of growth when once consumed would be essentially destroyed, and no soil could survive the exhaustion. There is no reason why the manure of man should be rejected by vegetation more than that of any other animal; and indeed it is not, for ample experience has proved that for most soils there is no better manure in existence. A single experiment will suffice to show that night soil may be so kept that there shall be no loss of its valuable gases, and consequently no offensive odor arising from it, while it may be removed and applied to crops without unpleasantness. All that is necessary to effect this wonderful change in night soil, and to turn it from its disagreeable character to one entirely inoffensive, is to mix with it a little charcoal dust, prepared muck, or any other good absorbent--thus making what is called poudrette. The mode of doing this must depend on circumstances. In many cases, it would be expedient to keep a barrel of the absorbent in the privy and throw down a small quantity every day. The effect on the odor of the house would amply repay the trouble. [Should pure night soil be used as a manure? What precaution is necessary in preparing hog manure for use?] The manure thus made is of the most valuable character, and may be used under any circumstances with a certainty of obtaining a good crop. It should not be used unmixed with some absorbent, as it is of such strength as to kill plants. For an analysis of human manure, see Section V. HOG MANURE. _Hog Manure_ is very valuable, but it must be used with care. It is so violent in its action that, when applied in a pure form to crops, it often produces injurious results. It is liable to make cabbages _clump-footed_, and to induce a disease in turnips called _ambury_ (or fingers and toes). The only precaution necessary is to supply the stye with prepared muck, charcoal-dust, leaf-mould, or any absorbent in plentiful quantities, often adding fresh supplies. The hogs will work this over with the manure; and, when required for use, it will be found an excellent fertilizer. The absorbent will have overcome its injurious tendency, and it may be safely applied to any crop. From the variety and rich character of the food of this animal, his manure is of a superior quality. [Why is the manure from butchers' hog-pens very valuable? How does the value of poultry manure compare with that of guano? How may it be protected against loss?]