33 ILLUSTRATIONS [Illustration] London E. & F. N. SPON, Ltd., 57 HAYMARKET New York SPON & CHAMBERLAIN, 123 LIBERTY STREET 1912 DEDICATED TO SIR JOHN TURNEY THE VETERAN OF THE LIGHT LEATHER INDUSTRY IN GRATEFUL ACKNOWLEDGMENT CONTENTS PAGE LIST OF ILLUSTRATIONS ix PREFACE xi I. DESCRIPTION OF THE PUERING AND BATING PROCESS 1 II. THE CHEMISTRY OF BATING 23 III. THE PHYSICS OF BATING 55 IV. THE BACTERIOLOGY OF THE BATE 87 V. ACTION OF ENZYMES 127 VI. ORIGINAL PAPERS ON BATING 147 VII. ARTIFICIAL BATES 178 VIII. PATENTS 193 IX. DRENCHING 233 X. ORIGINAL PAPERS ON DRENCHING 246 XI. BIBLIOGRAPHY 282 CONCLUSION 292 INDEX 295 ILLUSTRATIONS FIG. PAGE 1. Curve showing removal of lime by washing 6 2. Cubical “truck” for measuring skin _facing_ 8 3. Puer wheel " 13 4. Front elevation of puer wheel 13 5. End elevation and section of puer wheel 14 6. Sir John Turney’s scudding machine _facing_ 17 7. Curves of ash contents during puering 38 8. Diagram of volumenometer 62 9. " connexions of electrometric apparatus 76 10. Electrometric apparatus 78 11. Apparatus for measuring degree of falling 83 12. Curves obtained by measuring apparatus 85, 86 13. Improved apparatus for measuring degree of falling 86 14. Various forms of bacteria in puer liquors _facing_ 88