INTRODUCTION
Dogs ( Canis familiaris ) have been used for experimentation for centuries - since the mid 1600's when William Harvey studied circulation. The dog's cardiovascular and respiratory systems closely resemble humans and therefore were used to develop and test anesthetic and respiratory support equipment.
Research using dogs led to techniques for maintaining positive air pressure in the lungs and techniques for open-chest surgery. This research also resulted in surgery techniques to close a patent ductus arteriosus for correction of the "blue baby" syndrome.