In some works the practice was to cook the offal in steam-jacketed cookers. Now, when kippering offal, for instance, is being treated, the material, owing to lack of body, tends to coagulate at a certain stage in the process, a large volume of oil being liberated. This oil was skimmed and the residue, resembling a stiff mud, was removed to be wrapped in cloths for submission to extreme pressure in hydraulic presses. This action served to express a certain proportion of the oil remaining in the sludge. The compressed cakes were then transferred to a steam-jacketed drier to be reduced to meal. This process, which has not yet been completely superseded, suffers from being involved and prolonged, although these do not constitute the most adverse features. The greatest objections to it are the retention of an appreciable quantity of oil in the residue, even after subjection to pressure, which accordingly becomes associated with the meal. The last-named being sold for fertilizing purposes, the presence of the oil is objectionable, while the product also suffers from being low in ammonia. Furthermore, while the sludge is being pressed a pronounced volume of watery liquid is driven out to be lost down the drains. Seeing that this liquid carries valuable manurial constituents its loss is greatly to be deplored, and materially lowers the fertilizing--and financial--value of the meal. A variation of the foregoing process is made in other works, but it only tends towards greater inefficiency and heavier losses. In this case only the oil resulting from treatment of the material in the hydraulic press is recovered! A third system involves the passage of the pressed cakes through a continuous direct fire-heated drier. This method is particularly objectionable, not only from the offensive odours which are thrown off, but because the ammonia content of the waste undergoes serious depreciation, owing to the high temperature employed. In certain instances the herring offal is even charged into the apparatus without any attempt having been made to separate the oil! Such a system, as will readily be recognized, has nothing whatever to recommend it. It is the observance of such indifferent and unscientific methods as the foregoing which has been responsible for the commercial possibilities of fish-scrap to be belittled. The oil is undoubtedly ignored intentionally because fish oils are generally held to be worthy of inclusion only among the lowest grades of industrial oils. Nevertheless, were a chemist to be attached to such wasteful plants much needed reforms could be promptly introduced, although it is highly probable that the plants would be scrapped instantly at his instigation because of their lamentable inefficiency.