Patriotic Pooches(1943)

Answering a call for dogs to contribute to the war effort and join the "W.O.O.F.S." a small white puppy falls in with the others at a training facility manned by Gandy and Sourpuss. To clean them up, Gandy removes their fleas with a vacuum cleaner labeled "Flea Internment Camp". While the rest go through exercises and drilling, the puppy isn't big enough, so he's washed out. Moping around the beach, he sees a German submarine land and three fat pig Nazis emerge, one looking like Hitler. The pup alerts Sourpuss and the dogs, and a shootout ensues, the Nazis holed up in a shack. They toss out a bomb, but our hero tosses it back, blowing up the structure, and leaving the pigs as three hams with a swastika imprints. The pooch is truly patriotic, and gets a flag-waving medal ceremony.