CHONGQING, CHINA - FEBRUARY 16:  A worker observes white rats at an animal laboratory of a medical school on February 16, 2008 in Chongqing Municipality, China. Over 100,000 rats and mice are used in experiments every year for pharmaceutical research in the lab, where the temperature is kept at 24 degrees centigrade. Getty Images logo Getty Images 16 months ago

CHONGQING, CHINA - FEBRUARY 16: A worker observes white rats at an animal laboratory of a medical school on February 16, 2008 in Chongqing Municipality, China. Over 100,000 rats and mice are used in experiments every year for pharmaceutical research in the lab, where the temperature is kept at 24 degrees centigrade.