The position taken by the writer of this volume should be clearly understood. It is not the view known as antivivisection, so far as this means the condemnation without exception of all phases of biological investigation. There are methods of research which involve no animal suffering, and which are of scientific utility. Within certain careful limitations, these would seem justifiable. For nearly forty years, the writer has occupied the position which half a century ago was generally held by a majority of the medical profession in England, and possibly in America, a position maintained in recent years by such men as Sir Benjamin Ward Richardson of.