The head of a cobra is seen near a knife at a vendor's stall in Jakarta's Chinatown April 7, 2010. Five cups of snakes' blood are sold per day at a price of 50,000 rupiah ($5) each. Drinking snakes' blood, particularly that of a cobra, is believed to increase one's sexual virility, according to the vendor. REUTERS/Crack Palinggi (INDONESIA - Tags: ANIMALS SOCIETY ODDLY)