BYE-PRODUCTS OF THE LEATHER TRADES 271 



leather. Nevertheless, there is always a certain amount of 

 waste leather which only finds an outlet in the fertilizer 

 factory. Such material is usually steamed or roasted to 

 make it brittle, and then crushed in a disintegrator. It is 

 then mixed in with other materials, but is sometimes 

 solubilized by the action of sulphuric acid. Leather seldom 

 contains less than 30 per cent, protein. 



REFERENCES. 



"Chemical Fertilizers and Parasiticides," S. H. Collins, M.S., F.I.C. 

 (Companion volume in this series on Industrial Chemistry.) 

 " Wool Wastes," Part II., Section V., p. 75. 

 " Hoofs, Horns, Leather," Part III., Section II., p. 115. 

 " Gelatine, Glue, and Allied Products," T. Lambert. 



