22G Bureau of Farmers' Institutes. 



Dried Blood consists of blood obtained from slaughtered ani- 

 mals; it is prepared for market by evaporating, drying and grind- 

 ing. The color varies with the degree of heat employed in drying, 

 ranging from red to black. Red blood is of higher grade than 

 black blood. The red dried blood contains 13 to 15 per cent, of 

 nitrogen with very little phosphoric acid. Black dried blood con- 

 tains from 6 to 12 per cent, of nitrogen and usually some phos- 

 phoric acid. It is this lower grade of dried blood that is most 

 commonly employed in the manufacture of fertilizers. 



Dried Fish, Fish Scraps, and Ground Fish, consist of refuse 

 from fish-oil works, and fish-canning factories. The material 

 obtained from fish-oil works is the residue left after the extraction 

 of oil; it is prepared for market by drying and grinding. It is 

 qnito uniform in composition, containing 7 to 8 per cent, of nitro- 

 gen and as much or more phosphoric acid. The product obtained 

 from canning works consists of skin, bones, etc., of fish and is 

 very variable in composition. 



Tankage is slaughter-house refuse made up of miscellaneous 

 refuse matter such as bone, tendons, hair, hides, horns, hoofs, etc. 

 Two kinds of tankage are known in the market. One kind is 

 known as concentrated tankage and is made by evaporating sonic 

 of the fluids rich in nitrogen. This form of tankage contains 10 

 to 12 per cent, of nitrogen with only a little phosphoric acid. 

 The second kind is known as crushed tankage and consists of vary- 

 ing quantities of different parts of animal carcasses. As a rule, 

 the fat and gelatin are first removed by straining or boiling and 

 the residue is dried and ground. Sometimes a little slaked lime 

 is added to prevent loss of nitrogen by rapid fermentation. 

 Crushed tankage varies greatly in composition, the nitrogen rang- 

 ing from 4 to 9 per cent, and the phosphoric acid from 3 to 12 

 per cent. 



Garbage Tankage is material obtained by drying city garbage. 

 Sometimes it is partially charred. Its composition varies greatly, 

 containing nitrogen, phosphoric acid, and potash, but in small 

 proportions. It is usually richer in nitrogen than in any other 

 plant food. It is a low-grade fertilizing -material. Both its coin- 

 position and value as plant food are variable and uncertain. 



Hair is obtained from slaughter-houses; it is often mixed with 

 dried blood and other forms of animal matter. It contains about 

 15 per cent, of nitrogen. Wool-waste is much like hair in compo- 

 sition. 



Hoof Meal and Horn Dust are by-products containing 10 to 

 15 per cent, of nitrogen and about two per cent, of phosphoric acid. 



