The present work, which should by right have preceded the Laboratory Book (and which frequently refers to it as “L.I.L.B.”), attempts to deal with the general scientific principles of the industry, without describing in detail its practical methods (though incidentally many practical points are discussed). To complete the subject, a third volume ought to be written, giving working details of the various methods of manufacture; but apart from the difficulty of the subject, and the weariness of “making many books,” the methods of trade are so fluctuating, and dependent on temporary conditions that they have not the same permanent value as the record of scientific advance. As the present volume is intended to appeal both to the chemist and to the practical tanner, it must to a certain extent fail in both, since many matters are included which are already familiar to the former, and it is to be feared, some, which may prove difficult to the latter. For these and other imperfections the Author claims the indulgence of his Readers. The Author must here acknowledge his indebtedness to Dr. TOM GUTHRIE and to Mr. A. B. SEARLE for assistance in writing several of the chapters; to Dr. A. TURNBULL and Mr. F. A. BLOCKEY for much help in reading proofs and preparing the MS. for the press; and to the many gentlemen who have furnished or allowed him to use their blocks and drawings in illustration. THE YORKSHIRE COLLEGE, LEEDS. CONTENTS. CHAPTER I. _INTRODUCTORY AND HISTORICAL._ Primitive methods of leather manufacture -- Use of leather by the ancients -- Progress of leather manufacture in England -- Methods of production of leather -- Vegetable tannages -- Combination tannages -- Use of aluminium, iron and chromium -- Oil- and fat-leathers -- Difficulties of scientific treatment PAGE 1 CHAPTER II. _INTRODUCTORY SKETCH OF LEATHER MANUFACTURE._ The object of tanning -- Washing and soaking -- Removal of hair by liming -- Unhairing by putrefaction -- Unhairing and fleshing -- Deliming -- Bating, puering and drenching -- The vegetable tanning process -- Currying -- Alum, chrome and chamois leathers PAGE 7 CHAPTER III. _THE LIVING CELL._ The structure of cells -- White blood-corpuscles -- The yeast-cell -- Epidermis cells -- The building up of plants PAGE 10 CHAPTER IV. _PUTREFACTION AND FERMENTATION._ The nature of ferments -- Organised and unorganised ferments -- Classification of organised ferments -- General properties of ferments -- The alcoholic fermentation -- The action of enzymes or unorganised ferments -- The destruction of ferments by heat and antiseptics -- The products of fermentation -- The fermentations of the tannery -- Fermentation in bating and puering -- Fermentation in the tanning liquors -- Moulds and mildews -- Control of fermentation PAGE 15 CHAPTER V. _ANTISEPTICS AND DISINFECTANTS._