Hoofs, horns, hair, bristles, and wool, wool-waste and the intestines of animals, have been used as manures. Hoofs and horns form a regular source of artificial nitrogenous manure; the latter being obtained as a bye-product in the manufacture of combs and other articles. They are in the form of a fine powder; and in order to increase their rate of action, which is very slow, they are often composted in America with horse-manure before use. They have also been composted with slaked lime. There can be no doubt that such treatment increases very considerably their value. Their percentage of nitrogen seems to vary very much according to the kind of animal from which they are derived. In nine samples of horn the nitrogen was found to vary from 7-1/2 to 14-1/4 per cent; giving an average of 11-1/3 per cent. The nitrogen seems rarely to exceed 15 per cent. The amount of phosphoric acid they contain has been found by various investigators to range from 6 to 10 per cent. S. W. Johnson found only from .08 to .15 per cent in buffalo-horn shavings. In France what is known as "torrefied" horn has been used. This is horn which has been subjected to the action of steam. The nitrogen in this material is considered to be more active than in ordinary horn. According to Way, horns have been used for the hop crop with good results. Ground hoof is very similar in composition to horn, and contains about 14 to 15 per cent of nitrogen. Considerable quantities are now used. It must be remembered, however, that horns, hoofs, hair, bristles, &c., although rich in nitrogen, possess a comparatively low manurial value. The home production of these articles may be estimated at 6000 to 7000 tons. _Scutch._ Scutch is the name given to a manure made from the waste products incidental to the manufacture of glue and the dressing of skins. It contains about 7 per cent of nitrogen, and is manufactured in London to the extent of several thousand tons annually. _Shoddy and Wool-waste._