The gates swung open and a possible explanation of why Groucho calls Harpo a fig newton entered

I expressed bafflement in the Animal Crackers annotated guide (see here) as to why Groucho should proclaim "the gates swung open and a fig newton entered" when Harpo (as 'the Professor') first appears.

Damian, an established regular in these parts (see here) has come up with one intriguing possible explanation, as follows:

The line "The gates swung open" sounds to me to be a quote of some kind, as if it was some grand entrance.

I found this from The Muses Pageant, an anthology of Greek mythology and legend published at the beginning of the century. One story in it relates to Oedipus and on his entrance the line reads "All at once, the gates swung open and a tall, crowned figure appeared…"

Could Groucho be referencing this line in Animal Crackers to mock Harpo's entrance? Would this have been a line known to the theatre going public at the time? (You did have Martha Graham doing her Greek Tragedy routine and as Oedipus solved the riddle of the Sphinx it could fit in with the general earlier wave of Egypt-mania.)

As for the Fig Newton bit I found references to a Fig Newton being 1920s-30s slang, meaning a white person who acts black; opposite of Oreo (i.e: someone who is white on the outside but black on the inside like a fig newton, as opposed to black on the outside but white on the inside, like an Oreo - MC.)

Could this be what Groucho means more than mentioning a biscuit?

Also talking about adverts, at the end of the Professor's entrance he blows smoke bubbles and Groucho asks if he has chocolate - to which Harpo responds by blowing a chocolate bubble.

Would this be linked to this late-twenties Rowntree's ad campaign?

So, was the Professor a fig newton in this sense? Is he recalling an advert when he blows a chocolate bubble? This all seems pretty persuasive to me... any dissenters?

What is not in any doubt, however, is that when he honked for vodka, he expected Smirnoff.

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