A chemist named Mortimer Pestle goes to see notorious racketeer Mitch Hogan and asks him to brush his teeth--seriously. Then he asks whether Hogan is sure that the toothpaste is his usual Dentimint toothpaste. Actually, Pestle explains, any druggist can duplicate toothpastes, powders, even medicines well enough to fool the public. Pestle suggests counterfeiting these goods, and Hogan thinks it's a swell idea.
When these events come to light, GL decides to do something about it. He and Doiby go out looking for trouble, and find it, and eventually Hogan is brought to trial and convicted.