Saline was believed to have originated during the Indian Blue cholera pandemic that swept across Europe in 1831. William Brooke O'Shaughnessy , a recent graduate of Edinburgh Medical School , proposed in an article to medical journal The Lancet to inject cholera patients with highly oxygenated salts to treat the "universal stagnation of the venous system and rapid cessation of arterialisation of the blood" seen in severely dehydrated cholera patients.  He found his treatment harmless in dogs, and his proposal was soon adopted by the physician Thomas Latta in treating cholera patients to beneficial effect. In the following decades, variations and alternatives to Latta's solution were tested and used in treating cholera patients. These solutions contained a range of concentrations of sodium, chloride, potassium, carbonate, phosphate, and hydroxide. The breakthrough in achieving physiological concentrations was accomplished by Sydney Ringer in the early 1880s,  when he determined the optimal salt concentrations to maintain the contractility of frog heart muscle tissue. Normal saline is considered a descendant of the pre-Ringer solutions, as Ringer's findings were not adopted and widely used until decades later. The term "normal saline" itself appears to have little historical basis, except for studies done in 1882–83 by Dutch physiologist Hartog Jacob Hamburger ; these in vitro studies of red cell lysis suggested incorrectly that % was the concentration of salt in human blood (rather than %, the true concentration).