Bladder cancer in humans has been associated with cigarette smoking. 聽Since dogs can also develop this deadly cancer, they can serve as model for evaluating treatment methods. 聽In a study at the Massachusetts Institute of Technology, beagles were exposed to a carcinogenic chemical from cigarette smoke. 聽It turned out that those dogs urinating every four hours had only one third as much carcinogen left in their bladder as the animals voiding every eight hours. 聽Indeed some surveys on humans have also shown that in rural areas bladder cancer is less frequent than in urban areas. 聽The suggestion has been that men relieve themselves more regularly when they do not have to search for a bathroom. So where鈥檚 the nearest tree?