Lister carried out further experiments on the artery of a frog viewed under his microscope, which was the subject of water droplet of different temperatures, to determine the early stage of inflammation. He initially applied a water droplet at 80°F which caused the artery to contract for a second and the flow ceased, then dilated and the area turned red and the flow of blood increased. He progressively increased the temperature until it was 200°F. The blood slowed down then coagulated. In a letter dated 16 September 1855 Lister believed he had traced the process of inflammation. He continued the experiment on the wing of chloroformed bat, to widen his research focus. He used many different irritants. The most important discovery he drew from the experiments, was that if the irritant was sufficiently powerful it destroyed the tissue and if not destroyed the tissue was not able to carry out its normal function. On 18 June 1857, Lister presented a paper to the Royal Society "The early stages of inflammation". These series of experiments resulted in the publication of 11 papers between 1857 and 1859. They included the study of the nervous control of arteries, the earliest stages of inflammation, the structure of nerve fibres and the study of the nervous control of the gut with reference to sympathetic nerves. Indeed, he continued the experiments for three years, until he was appointed Regius Professor of Systematic Surgery at the University of Glasgow. Throughout his life, Lister believed that the papers on microscopy and physiology that he presented to the Royal Society in 1857, were his most important.