"Melancholia" by Antonio Dacosta
Apparently melancholia is more prevalent in cats than I originally thought. Here we find yet another (sad) cat in a well known painting. This must mean one of two things. Either Dacosta was well aware of this prevalent feline disorder, and thought it a great painting subject, or his career was in a tailspin and he included a cat out of desperation to make a sale. I think I might be on to something.