The purpose of this monograph is to bring together in one volume some of the more recent knowledge of the cellular and biochemical constit­ uents of sheep's blood. Limitations of the space available have precluded a complete discus­ sion, but a number of good reviews have been published within the last few years on certain specific aspects and these have been referred to in the extensive bibliography. There is inevitably some overlap in the material discussed arising from duplication of interest and from the close association of the subject matter. The authors were asked to discuss normal values and the changes brought about in these by physiological stresses, particularly those imposed by pregnancy, age, lactation, and changing nutrition. In some cases, where it was considered suJtable, the response to certain pathological conditions have also been discussed. It is hoped that the monograph will be of value to those using sheep in comparative research into veterinary and human medicine as well as to students of ruminant physiology. Wellington/New Zealand, April 1975 M. H. BLUNT Table of Contents Distribution and Dynamics of Body Fluids in Sheep W.V. MACFARLANE. With 1 Figure .................................. . Introduction .................................................... .