Translation:All cats are the same: fat animals that only want to eat and sleep.
Let me have cats about me that are fat; thick-headed cats, and such as sleep o' nights. Yon Cassius has a lean and hungry look. He thinks too much. Such cats are dangerous.
By the way, if you haven't seen the film with Marlon Brando as Mark Antony and James Mason as Brutus, find it and watch it.