ABSTRACT
The scientific search for the agent of combustion (respiration) began with Robert Boyle's experiments with flames and animals in vacuo (1660). John Mayow vague vocabulary was fanciful and confusing, he understood that the principal object of breathing is to bring a supply of "nitrous air" to the blood to maintain the combustion process by which body warmth is produced. John Mayow chemist and physiologist, first suggested in 1674 that dark venous blood turned bright red by taking up a specific ingredient in air necessary for life, which he termed the nitro-aerial spirit. The first known attempt to evacuate gases from blood had been made by Robert Boyle when he released large quantities of "air" from sheep's blood in a vacuum created by his air pump. In 1862 Hoppe-Seyler noted the characteristic absorption spectrum of the coloring matter of blood; and in 1864 he isolated the pigment as a crystalline compound which he called hemoglobin.
