Recently research scientists discovered” that there are Antibiotics in the soil of earth , these Antibiotics can clean up and kill the most obstinate kind of bacteria , which prove that soil is a Disinfectant. In a new study scientists said that there are some kinds of soil which can remove the most obstinate kind of bacteria. Today, scientists are looking for manufacturing a killer for the most obstinate kind of bacteria extracted from soil. After many tests in laboratory they found that during 24 hour soil can remove an entire colony of bacteria but the same colony had multiplied 45 times without mud.”(Quoted from:http://kaheel7.com/eng/index.php/secrets-of-quran-a-sunnah/132-seven-scientific-facts-testify-that-mohamed-is-sincere see also: New Antibiotic from Soil Bacteriahttp://www.the-scientist.com/?articles.view/articleNo/41850/title/New-Antibiotic-from-Soil-Bacteria/}
Long time ago: (about 1400 years ago) prophet Mohammed said (ground was made for me as a place to prayer and also a method to be pure) [Narrated by Muslim].