Beau’s hypothesis was incredible to Rufus, and yet he stated it with complete sincerity. Gators lived in rivers, which were the ultimate destinations of all sewage. Modern municipalities made efforts to treat their sewage, but sooner or later it did have to go somewhere. Sewage treatment was designed to handle poo, and little else. Complicated molecules such as pharmaceuticals tended to pass through unaltered. You could find evidence of a population’s usage of drugs, legal and illegal, in its sewage.