of this movement has been traced to the Fox sisters who in 1848 began claiming the ability to communicate with the dead. The religious movement would remain popular until the 1920s, when renowned magician Harry Houdini began exposing famous mediums and other performers as frauds (see also Harry Houdini#Debunking spiritualists). While the religious beliefs of Spiritualism are not presented as science, and thus are not properly considered pseudoscientific, the movement did spawn numerous pseudoscientific phenomena such as ectoplasm and spirit photography. The principles of homeopathy were first formulated in 1796, by German physician Samuel Hahnemann. At the time, mainstream medicine was a primitive affair and still made use of techniques such as bloodletting. Homeopathic medicine by contrast consisted of extremely diluted substances, which meant that patients basically received water. Compared to the damage often caused by conventional medicine, this was an improvement. During the 1830s homeopathic institutions and schools spread across the US and Europe. Despite these early successes, homeopathy was not without its critics. Its popularity was on the decline before the end of the 19th century, though it has been revived in the 20th century. The supposed Martian canals were first reported in 1877, by the Italian astronomer Giovanni Schiaparelli. The belief in them peaked in the late 19th century, but was widely discredited in the beginning of the 20th century. The publication of Atlantis: The Antediluvian World by politician and author Ignatius L. Donnelly in 1882, renewed interest in the ancient idea of Atlantis. This highly advanced society supposedly existed several millennia before the rise of civilizations like Ancient Egypt. It was first mentioned by Plato, as a literary device in two of his dialogues. Other stories of lost continents, such as Mu and Lemuria also arose during the late 19th century. In 1881 the Dutch Vereniging tegen de Kwakzalverij (English: Society against Quackery) was formed to oppose pseudoscientific trends in medicine. It is still active. 20th century Among the most notable developments to pseudoscience in the 20th century are the rise of Creationism, the demise of Spiritualism, and the first formulation of ancient astronaut theories. Reflexology, the idea that an undetectable life force connects various parts of the body to the feet and sometimes the hands and ears, was introduced in the US in 1913 as 'zone therapy'. Creationism arose during the 20th century as a result of various other historical developments. When the modern evolutionary