According to the storyboard (included as a bonus feature on the "Looney Tunes" DVD set), this cartoon originally was to have had one more scene at the end. As Clyde the cat floats via balloon to "Cat Heaven," the mice are shown inside the house, in front of the fireplace, roasting cheese clumps (shaped like marshmallows) on toothpicks. Clyde is seen through the window, blissfully drifting skyward.
Hubie and Bertie are shown accurately (for the time) scrubbing up for surgery.
Acme, the WB purveyor of choice, makes an appearance here, providing both flour and x-ray equipment.
Claude and his rodent companions live in the very latest in furnished homes of the postwar era. And it's drawn in perfect detail, too, a credit to the animators.