The high percentage of ammonia, namely 7·37 per cent., deserves especial notice inasmuch as it compares with a yield of 4·5 per cent., which is the average figure recorded with fertilizing meal obtained from steamed bones. It may possibly come as a surprise to many to learn that it is the proportion of the nitrogenous content, as represented by the ammonia, rather than the phosphoric acid content, which really determines the commercial value of this manure. The higher the figure to which the ammonia figure can be forced the more attractive the price which the fertilizer will command upon the market. Thus, under normal conditions, every 1 per cent. rise in the ammonia constituent will increase the price of the bone-meal by 14s.--$3.50. On the other hand, a 1 per cent. increase in the proportion of superphosphate only serves to increase the price of the meal by 11d. to 1s. 2d.--22 to 28 cents. The grease obtainable from green bones varies somewhat. It is affected to a marked degree by the skill and care with which the butcher wields his knife. If the bone should be scraped very clean and carefully, naturally the bulk of the attached fat is removed. But an average collection of green bones will yield about 15 per cent., or 360 lb., of fat per ton of bones treated, while the dry bone-meal will range from 1,286 to 1,344 lb. Bones which have been collected from marine store dealers and rag-and-bone merchants are not so liberal in fat yield. The repeated cooking to which they have been subjected in connection with the preparation of dishes for the table relieves them of approximately 5 per cent. of the fat which they originally carried, i.e. in the raw condition. Consequently, degreasing only enables about 10 per cent., or 250 lb., of fat to be recovered from every ton of bones treated. In this instance the bone-meal yield may be set down at 1,568 to 1,680 lb. per ton of bones. The grease remaining in the meal varies from 0·5 to 1 per cent. As may logically be supposed, cattle-slaughtering for food produces large quantities of blood. This is an extremely valuable residue, and so is carefully collected in suitable vessels. It is then transferred to shallow receptacles and permitted to stand for a time. Blood is composed of two fundamental constituents--the serum and the clot respectively. The former, which is the albumen, is the glutinous-like, yellowish liquid which comes to the surface, the clot settling to form as it were a sediment. The serum is recovered by skimming with a suitable device, to be distributed in extremely thin layers, applied with a brush, to dry. Such a careful procedure is imperative owing to the difficulty of drying out albumen. When dry the blood-albumen is peeled in the form of thin flakes. Its applications are numerous, one of the most important being its employment for the clarification of sugar. The clot is likewise secured to be sent to the special plant, where it is also dried.