The germ of the musical Russian nineteenth century in two measures of Bach

I have noticed these two measures of marvelous chromatic movement every time I make my way through J.S. Bach's Well-Tempered Clavier, but this time I decided to document it and share my delight. Here are measures thirteen and fourteen of the tenth fugue of the first book.

You can listen to it played at a very leisurely tempo here. I hope you hear what I hear (and what I imagine Tchaikovsky, Borodin, and Glazunov heard as well).

And while I have your ear, make sure to check out this post concerning what Gershwin might have heard in the second prelude of the first book of the WTC.