Short accounts of the more common diseases, their causes, symptoms, and treatment, affecting the domesticated animals have been introduced. “Here, however, it may be useful to repeat the cautions given in other parts of this volume, as to the impropriety of unnecessarily meddling with the healing art or neglecting a prompt application” (where and when possible) “to a duly qualified practitioner in all cases demanding medical or surgical aid.” These remarks of Mr Cooley are as applicable to cases of Veterinary as to those of Human Medicine. Numerous authors have necessarily been consulted; a list of them, and the titles of their works from which information has been derived, will be found at the end of the second volume. When extracts have been introduced _verbatim_ the authority is quoted in the body of the book. Many of my scientific _confrères_ have rendered me valuable aid in preparing this edition; but I am particularly indebted to my accomplished and zealous friend Mr John Gardner for his hearty and constant co-operation; to Dr Lionel Beale for his kindness in revising the articles on “Urine,” “Urinary Diseases,” &c., as well as for the use of cuts from his celebrated works on these subjects; to my friend and former pupil Mr F. Woodland Toms for revising and rewriting the articles on “Sewage” and “Water;” and to my assistants Mr James Bayne and Mr Cuthbert Neison for correcting “proof.” The laborious task of preparing a sixth edition of ‘Cooley’ having been accomplished, it is hoped that, due consideration being given to the magnitude of the work and to the great variety of the subjects treated, it will be found to be practically free from important errors, and that it will meet with, at least, the same gratifying reception as that accorded to its predecessors. RICHARD V. TUSON. CHEMICAL LABORATORY; ROYAL VETERINARY COLLEGE, LONDON. _January, 1880._ PREFACE