In  mine and my brother's collection of Edison cylinder records,  (late 1800's, early 1900's,) I was delighted to find two actual dance records:   one was  The Lancers Quadrille,  the other a "Plain Quadrille"   WAY before microphones were invented,  so they used  Megaphones:  like cheerleaders of today. They yelled out  the bare bones of the calls through the megaphone:   in high Society,  you were supposed to have taken lessons and only needed   "prompts"   similar to  actors in plays having  a backstage person (the Prompter)  ready to help actors who forgot their lines. 
    The available records   only played for  either 2 minutes or later,  4 minutes. 
Interesting to hear the  caller scream out  "R  I G H T  A N D   L E F T"
meaning  "Right and left  over AND back"
     Ralph Sweet
 
In a message dated 10/13/2016 6:11:14 P.M. Eastern Daylight Time, trad-dance-callers@yahoogroups.com writes: 

> I’m curious about calling before microphones became ubiquitous. Is
> there much information about callers prior to sound amplification?
> Did they drop out quickly to save their voices? Were the dances just
> known by enough dancers that they were danced without calling?
>
> Lindsey

And Jacob replied: "Here are some quotes from Page's 1937 book:
"The best prompters baby their throats as if they were opera singers.
Their greatest horror is laryngitis. They don't drink olive oil or wrap
up in pink cotton batting, though; strange as it may seem, the oftener
they call, the better their voice. They claim that six nights a week
are better than one or two, because their vocal cords are really
exercised then and so become stronger."
So it sounds like Ralph Page, and the other callers of his generation,
didn't believe in trying to "save" their voices."

Which prompts me to ask what other callers do to take good care of their
voices. It's hard when you're partway through a heavy-duty event and
your voice starts to feel ragged.

Kent Gilbert, in Berea, gave me his recipe for a
disgusting-but-effective gargle that helped me hang on to my voice
during a long, intense week. It's equal parts Listerine, hydrogen
peroxide and warm salt water. Gaa-ACK! But it definitely cleared and
soothed my throat. Just warm salt water all by itself is supposed to be
great, too.

How about the rest of you? What do you do to take care of your voices,
especially during multi-day gigs, especially-especially if there's
flying involved?

Kalia (getting ready for an English dance weekend near Santa Cruz)