Sentence:  Blockheads, friends of my heart and liver, cousins of my tripe, are you ignorant that this symposium is as authentic as any of those tales of the Greek <WSD>Calends</WSD>, which you swallow and digest so easily, [...]? 
Meaning of the word marked with <WSD> tags:  "Often with initial capital": the first day of a month, particularly  the first day of a month of the Roman calendar.