In a previous chapter I have described the reclamation process practised by the military authorities in connection with bones arising from the cutting-up of meat for the army, as well as those recovered from the swill-tubs. As indicated, however, exploitation is conducted only to a certain point, when the bones are handed over to the degreasers. It is then that the true recovery of the commercial constituents of the bone commences. The bone is an invaluable friend to the human race as an article of commerce, though it is to be feared that what may be described as the “bone tree” is only imperfectly understood. Its far-reaching value as a fertilizer is certainly appreciated, but this really represents the final application of the article, and may be said to be the only remaining field of utility for the ultimate residue of a residue. Bones enter into a wide range of industrial and manufacturing operations. For this reason they should be carefully gathered and retained for surrender to recognized collecting mediums rather than suffer abandonment or destruction. The housewife is prone to regard them as mere waste when she has extracted the utmost recoverable value therefrom in the kitchen. She may possibly retain them until the itinerant specialist in this commodity, to wit, the rag-and-bone man, comes round, in which event it is sure to be sped once more on a journey of industrial exploitation. But at least one-third of the bones which enter the households of Britain escape reclamation. They are wantonly wasted, and it is to be feared that the kitchen stove is mainly responsible for this loss. The volume of bones which should be forthcoming from domestic circles in Great Britain, were the dictates of thrift religiously followed, is scarcely appreciated, but it is estimated that the supply should be at least 100 tons per week from every million members of the population. In these islands the bones are divided into two broad classes. The one division, comprising what is known as “green” (raw) bones, represents those collected from butchers’ shops, bacon-cutting works, and other similar sources. The second class, defined as “streeters,” include those forthcoming from the recognized collectors of such waste, hotels, restaurants, clubs, and private houses, and are those which have been passed through one or more cooking processes. In the case of green bones it is customary to digest them, when really fresh, with open steam to recover the edible fat. Shank and marrow bones, as distinct from rough bones, are also able to yield a certain proportion of edible fat, and after having been digested or boiled still retain a considerable percentage of grease which it pays to extract. Consequently these, together with a certain quantity of less fresh green bones, and the streeters, are then passed through the benzine extractor to be degreased down to 1 per cent.