I am privileged to-day in having been invited to give this address, but I feel that I am particularly privileged also in that, so far as I can discover, this is the first occasion in the annals of the Royal Society of Edinburgh on which a veterinarian has been asked to address the Society on matters concerning the diseases of animals.

The Veterinary profession has long been recognised as a handmaid of Agriculture but, like her sister profession Medicine, her services, until comparatively recently, have been based on knowledge acquired by long experience derived from trial and error, as distinct from planned experiment based on scientific principles.