Like a bad lobster in a dark cellar

I’ve never learned to care for Dickens but last night I decided to read A Christmas Carol for the first time in – and its odd I know this so precisely – twenty-one years.  And I find there this maddeningly bewildering line describing the Marley-possessed knocker.

And then let any man explain to me, if he can, how it happened that Scrooge, having his key in the lock of the door, saw in the knocker, without its undergoing any intermediate process of change—not a knocker, but Marley’s face.

Marley’s face. It was not in impenetrable shadow as the other objects in the yard were, but had a dismal light about it, like a bad lobster in a dark cellar. It was not angry or ferocious, but looked at Scrooge as Marley used to look: with ghostly spectacles turned up on its ghostly forehead. The hair was curiously stirred, as if by breath or hot air; and, though the eyes were wide open, they were perfectly motionless. That, and its livid colour, made it horrible; but its horror seemed to be in spite of the face and beyond its control, rather than a part of its own expression.

I would’ve taken it as nonsense but it felt too specific an image.  So I dug a bit and have one definite answer and one related image.  First, the easy answer – rotting marine line tend to shine due to a luminescent marine bacteria that reproduce to the point of visibility as the host decays.  It seems to happen on occasion with fish in aquariums and often baffles the owners.

For the related image – it is an apparently famous quip by American politician John Randolph about an an opponent (generally identified as Henry Clay, sometimes as Edward Livingston) – “He is a man of splendid abilities but utterly corrupt. He shines and stinks, like a rotten mackerel by moonlight.”  The phrase ‘mackerel by moonlight’ seems also to have survived to some degree in American politics to describe a corrupt politician.