=Receiving Tank.=--This is preferably a closed type of tank with an air vent to allow displacement of air when blowing blood. It is preferably situated above the cook tank with an admittance valve between them so that blood can be lowered to the cooking tank at will. =Cooking.=--Blood should be “_baked_,” not boiled. By this is meant, the steam should be admitted slowly and the heat dispersed through the mass rather than boiled violently, by admitting high pressure steam. The blood, by this method, seems to coagulate in larger grains, and, in pressing, a larger proportion is retained in the cloths, while the serum or white water draining away is of a lighter color, with the net result that the yield of blood is better. =Pressing.=--The pressing is performed in the same manner as described for tankage, except that the material is handled dry. The waters from cooking, as well as from pressing, are saved for evaporation as tank water. Blood when pressed properly is “caked.” It should be broken up before being passed to the dryers. =Purity.=--Means should be provided and arrangements made to keep all raw or fluid blood free from water and manure. Frequently cattle that are hay or grass fed, have a draining from the stomach via the mouth when hung, and comparatively large quantities of undigested food are spilled. This should be collected before the animal is stuck and prevented from mixing with the blood. =Storing.=--After drying, blood should be cooled and stored in piles on the floor in dry rooms to be put in bags at the time of shipment. It is usually unnecessary to grind or screen it. It should be dried to 8% moisture. =Quick Handling.=--Blood is so highly susceptible to decay that it should be handled quickly and with as little contact with air as possible. =Tankage.=--This name embodies the dried material from the residue in the tanks after cooking in digesters, and pressing. It is classified into several grades. Digester tankage, is usually sold for stock foods. No. 1 tankage of commerce, has a high nitrogen content and low percentage of bone, it is usually produced from beef tanks; No. 2 tankage is low in nitrogen or ammonia, as it is known to the lay-mind, and high in bone. The usual comparative analysis is: Blood No. 1 No. 2 Bone Phosphate ... 10% 28% Ammonia 16-17% 10-12% 6-8% =Quotations and Values.=--Tankage and blood is usually sold on its value per unit of ammonia. That is to say, if blood be quoted at $3.00 per unit of ammonia and analyzes sixteen per cent, it sells for $48.00 per ton. Tankage may contain eleven per cent ammonia and twelve per cent bone phosphate, quoted at $2.75 per unit, and 10c per unit respectively, which would make the relative market $31.45 per ton.