Date: Tue, 2 Jun 1998 23:21:49 +0200
From: Roberto Serrai
Subject: Is it military slang?

Hi,
my name is Roberto Serrai, I am an italian professional translator.
I am currently working on Bruce Robinson's ("The Killing Fields",
screenplay) first novel, "The Peculiar Memories of Thomas Penman."
In this book, a character gets wounded at Passchendaele in WWI.
The Germans take him to an hospital in Koblenz:

"It was a story his grandson liked to hear. He liked hearing about the
Germans and magic flies. The hospital in Koblenz was full of both and
Walter [the character] genuinely never knew which one of them saved
him."

Has anyone, please, an idea about what those "magic flies" could be?
I've looked everywhere...
Thanks,

Roberto Serrai