Mickey Mouses First Dog? (Not as stupid as it seems)?

Okay, well for starters, I'm assuming it was his dog, because he was the one who shoved it down the sewer, then laughed his head off.

Anyways, it's this old cartoon about this dog, who I'm assuming was Mickey's, in the sewer, and it's basically a nightmare. They torture the poor thing. It's all in black and white, and it's older.

Anyways, in the end of the cartoon Betty Boop shows up, and the dog, well, FANCIES her to say the least I guess.

Anyways, does anyone know the dogs name, or the name of the cartoon? I wanna do more research and figure out if my theory is true.

Thanks in advance!