The process, it will be observed, is continuous, while the benzine may be used over and over again. All that is required is to place a sufficient quantity of the solvent into the circuit to carry out the operation with the essential efficiency. Naturally, the quantity involved varies with the size of the plant and the work to be fulfilled, but it may run up to 5,000 or more gallons. The plant is generally laid out upon the unit principle, which is the most satisfactory, because it facilitates the adaptation of the installation to the volume of work in hand. One or more units can be shut down during the “off” period, allowing the remainder to be worked up to their full capacity, which, of course, is the most efficient and economical method. The losses of benzine are very low--not exceeding 1 per cent. of the weight of the raw material treated. In fact, there are many installations in operation where, over a period of one year, the benzine loss recorded is actually below 1 per cent. This factor is vitally influenced by the care and attention bestowed upon the plant. If it be carefully tended, all joints being kept in the tightly packed condition, and the condenser maintained in a high degree of efficiency, the benzine loss may be reduced to an infinitesimal degree, the value thereof representing but an insignificant fraction of the value of the increased yield of oil and fat. The solvent acts upon the grease only. It does not affect in any way the gelatinous material, and, consequently, the nitrogenous or ammonia value of the ultimate meal is considerably enhanced as compared with the results achieved with the digesting plant. The meal is discharged from the extractor in a dry crisp condition ready for immediate grinding, and is admirably adapted for poultry and cattle feeding. No traces of the benzine remain. The bones may be ground immediately, if desired, but if these should be forthcoming in sufficient quantity they should be passed on to the glue and gelatine plant. There is no necessity to submit them to a further degreasing process, because this has been completed in the one operation in the extractor. As a rule, however, with installations devoted to the treatment of condemned meat and other offal, the bones are not forthcoming in sufficient quantities to justify the attachment of a glue recovery plant although, of course, they can be sold to other works specializing in this work. It is merely a question as to whether it would pay to transport the degreased bones to the glue works. If not, they can be ground up to be utilized as fertilizer, for which, it is needless to say, a good price can be obtained.