The stooges are pharmacists who invent a fountain of youth formula that can turn old people young. They turn an old lady into a beautiful young woman, but when her husband takes the formula it turns him into a gorilla.
Acting
Shemp's nervous energy versus Moe's simmering rage — pure alchemy.
Practical Effects
Gorilla suit commitment that transcends budget limitations entirely.

Director
Jules White
Trivia, insights & behind the scenes
This was one of Shemp Howard's final shorts before his death in 1955; he reportedly filmed this while already in declining health, making his manic energy even more impressive.
The 'fountain of youth' premise was recycled from the 1949 Stooges short 'All Gummed Up,' but with the gorilla twist added because apparently audiences demanded more primate husbands.