• CONTENTS. 7 



Department Bulletin No. 148 — Continued. Pa g e - 



A mother-starter can 13 



Preparing the starter 15 



Summary and conclusions 16 



Department Bulletin No. 149. — The Use op Radioactive Substances as 

 Fertilizers: 



Introduction 1 



Properties of the radio-elements 3 



The influence of radioactive rays on plants 5 



Composition of radioactive manure 8 



Field tests with radioactive manure 8 



Catalytic fertilizers 11 



Summary 13 



Department Bulletin No. 150. — Utilization of the Fish Waste of the 

 Pacific Coast for the Manufacture of Fertilizer: 



Introduction 1 



Technology of canning 4 



Production of canned salmon 12 



Centers of the industry 13 



The waste produced in the canning of salmon 16 



Other salmon-preserving industries 22 



Chemical composition of the raw cannery waste 23 



Methods of disposal of waste 25 



Amount of waste utilized in the various centers 27 



Fish scrap from salmon waste 28 



The products 32 



Methods proposed for the treatment of salmon cannery waste on a large 



scale 36 



The small by-products plant operated as an integral part of the cannery.. . 44 



Cost 49 



The production of a mixed fertilizer from fish scrap and kelp 52 



Fish scrap from other fish 66 



