This process, to which I have also devoted adequate attention previously, not only enables a product of high quality to be obtained, enabling it to command an enhanced price in the market, but it also conduces towards the retention of the nitrogenous contents of the meal. From the fertilizing point of view this is the main end to be achieved. Colour of the meal is another factor which demands recognition. It plays a far more prominent part in the commercial value of the product than might possibly be conceived. The American drying system, operating along direct fire-heated lines, while efficient so far as it goes, namely, the elimination of the moisture, yields a darker coloured meal, owing to the high temperature which has to be used, while, of course, the nitrogen content is lowered by such practice. The vacuum system has also proved highly efficient for the production of cod-liver oil. The temperature of rendering being low gives an oil of superior colour and odour, two factors of vital importance when the oil is being extracted for medicinal purposes. This is a somewhat delicate product to manufacture, especially when the livers are in a state of partial decomposition, because in this instance colour and sweet taste are particularly vital and difficult to assure. I have referred to the circumstance that fish oils commercially rule low in the scale of industrial oils. But even fish oils possess one feature common to the highest grades of oils. They carry a certain proportion of glycerine. During the war the oil extracted from fish-scrap and offal was subjected to further treatment to swell our domestic supplies of this indispensable commodity. Even under normal conditions the reclamation of oil from fish waste to secure this glycerine offers further inducement to this phase of industry, and is also capable of considerable development. Fish oils are also destined to play a more prominent part upon the table than has been the case heretofore. Their inherent fluidity and refusal to solidify, except at low temperatures, have hitherto reacted against their use in this direction. But the increasing demand for margarine as a substitute for butter, and the discovery of the hydrogenating process for eliminating the two outstanding defects, have invested the future for fish oils with additional significance, more especially as by the hardening process, as it is called, the pungent taste and aroma so distinctively of the sea and its inhabitants are removed. By virtue of this discovery fish oils are entering more and more extensively into the manufacture of margarine. The circumstance that they yield a product so closely allied to the genuine article from the dairy as to be difficult of detection, except by elaborate investigation and specialized methods, has served to accentuate this tendency.