Originally published in 1921. PREFACE TO THIRD EDITION: FOR many years the sole use found for milk curd was in the manufacture of cheese to be used as a food- stuff. Skimmed or separated milk, produced in large quantities as a by-product in butter-making, was fed to pigs or even run into a stream. It is only through the scientific researches of the past few decades that the true value of albuminoid substances has been realised and that the manufacture of casein from skim milk has become a practicable proposition. In- cidentally to this, the preparation of milk sugar has become a possibility, and the easy digestibility of this product has resulted in its being foods and similar preparations. used in infants It is easy to understand that our knowledge of casein is somewhat imperfect, especially as regards its manifold uses, but as time goes on it will become more and more appreciated in industrial applications since it has valuable properties which are not easily found in any other product. Communications on the subject in the technical press are rare, consequently it appeared desirable to the reviser to prepare a work dealing with this material. The first part of this book treats upon the pre- of the paration of curd from milk, by decomposition suspended casein compound with acids or with rennet, and the purification and drying of the precipitated casein. Following this, the composition, properties, then and reactions of casein are touched upon follows a description of the use of casein in the manufacture of paints, distempers, putties, plastic the masses, artificial ivory, and other materials modes of applying these and their special features. The use of casein as a dressing for paper and cloth and its employment for waterproofing and other pur- poses is also described, and finally there are chapters on the use of casein in nutrient preparations, and the compounds of casein employed for medicinal purposes. In compiling this work the reviser has endeavoured to bring together as much useful information as possible, and acknowledges his indebtedness to. many investigators who are mentioned in the text and footnotes. LONDON, August, 1921. Contents include: PREFACE iii CHAPTER I. INTRODUCTION 1-2 CHAPTER II. CASEIN ITS ORIGIN, PREPARATION AND PROPERTIES. The preparation of casein Heating pans for the preparation of casein Steam generator Washing the curd Drying cylinders Vacuum eva- porators Purifying the curd Filter press Vegetable casein . . 3-29 CHAPTER III. VARIOUS METHODS OF PREPARING CASEIN. Hatmakers method Halls method Spittelers method Process of Mierisch and Eberhardt Riegels method Szekelys patent Bel- lamys method Hoppe-Seyler method Besanas method Justs method Ricard and Riches patent Dunhams patent Baechlers patent, ...- 30-40 CHAPTER IV. COMPOSITION AND PROPERTIES OF CASEIN. Analyses of caseins Properties of casein Reaction with various reagents Estimation of casein Analyses of industrial caseins.... 41-57 v VI CONTENTS. CHAPTER V. t CASEIN PAINTS. PAGES Sifting machine Marble lime colour for outside work Casein enamel paint Cone paint mill Cold-water paint in powder form Caseinlime colours Pure casein paints for walls, etc...