Tetrapod probably had a three-chambered heart, as do modern amphibians and reptiles, in which oxygenated blood from the lungs and de-oxygenated blood from the respiring tissues enters by separate atria, and is directed via a spiral valve to the appropriate vessel — aorta for oxygenated blood and pulmonary vein for deoxygenated blood. The spiral valve is essential to keeping the mixing of the two types of blood to a minimum, enabling the animal to have higher metabolic rates, and be more active than otherwise. The difference in density between air and water causes smells (certain chemical compounds detectable by chemoreceptors) to
The Sacrament of the Body and Blood of Christ—Against the Fanatics both sides became more firmly entrenched into their positions. The Sacrament of the Body and Blood of Christ—Against the Fanatics The Sacrament of the Body and Blood of Christ—Against the Fanatics is a book by Martin Luther, published in late September or early October 1526 to aid Germans confused by the spread of new ideas from the Sacramentarians. At issue was whether Christ's true body and blood were present in the Lord's Supper, a doctrine that came to be known as the sacramental union. The of Christ's true body and blood in the Lord's Supper was a controversial issue at