CONTENTS. 5 



Department Bulletin No. 782. — A Study of thr Alkali-forming Bac- 

 teria Found in Milk. Page. 



Historical review 1 



Definition of the alkali-forming groups of bacteria 2 



Cause of the alkaline reaction in milk 2 



Sources of the alkali-forming bacteria 9 



Morphology and growth 10 



Sources of nitrogen 11 



Fermentation of carbohydrates 12 



Fermentation of alcohols 17 



Fermentation of salts of organic acids 19 



Reduction of nitrates and nitrites 30 



Arbitrary grouping of the alkali-forming bacteria from milk 33 



Summary and conclusions 35 



Literature cited 39 



Department Bulletin No. 783. — The Rice Moth. 



Introduction 1 



Nature of injury 1 



Descriptive 2 



Synonymy : 2 



The moth 2 



The egg. 3 



The larva 3 



The pupa 4 



Distribution 4 



Food habits 4 



Reported injuries 5 



Life history 7 



Associated insects 8 



History and literature 9 



Control measures 10 



Destruction by heat 11 



Fumigation methods 12 



Summary 13 



Literature cited 14 



Department Bulletin No. 784. — Lessons on Potatoes, for Elementary 

 Rural Schools. 



Introduction 1 



Lesson I. Selection of seed potatoes in the field 4 



Lesson II. Harvesting and grading potatoes 6 



Lesson III. Marketing potatoes 7 



Lesson IV. Winter storage 9 



Lesson V. Potato judging 10 



Lesson VI. The potato tuber (and plant) structure 12 



Lesson VII. Place of potatoes in the rotation 13 



Lesson VIII. Soils — kind, preparation, fertilizers, etc 15 



Lesson IX. Planting potatoes, including the treatment of seed 16 



Lesson X. Cultivation — first. Later cultivation 18 



Lesson XI. Potato-crop pests — Insects and diseases, how to combat them. 19 



Lesson XII. Uses of the potato — The potato as a food 21 



Supplement 23 



Publications relating to potatoes 24 



Department Bulletin No. 785. — The Field Testing of Copper-spray 

 Coatings. 



The persistence of sprays containing copper 1 



A practical method of field testing 2 



Field trials ^ 



Apple leaves at Crozet, Va | 



Bearing grapefruit trees at Winter Park, Fla 5 



Citrus nursery stock at Bradentown, Fla 6 



Celery at Bradentown, Fla ^ 



Directions for use ° 



Conclusions ^ 



