You know what a _hunch_ is, don't you?
There's something there about somebody having a cataract, and that's something the matter with your eyes; Mr.
Temple had one.

So maybe that feller L.that he met again is an eye doctor.

Long before the war started they told Mr.Temple maybe he ought to go to Berlin to see the eye specialists there--'cause they're so fine.

So maybe the spy is a surgeon and L.is an eye doctor.

It says how he met him again on account of somebody having a cataract.