Argentine "Prostitution" stamps.

I was recently given 4 Argentine "prostitution" stamps all from the city of
Rosario. The story that came with them has it that between 1910 and 1935
all registered prostitutes in the cities of Rosario and Buenos Aires had to
have a medical examination every Wednesday. If found healthy the doctor
would issue a certificate with a "servicio sanitario" stamp attached and the
ladies would, if requested, show it to their clients. These stamps cost 1
peso in Rosario and 2 pesos in Buenos Aires. I would like to have some
points confirmed/explained.

1. Why was this required only of the prostitutes of Buenos Aires and
Rosario?
2. Why were the ladies in Buenos Aires charged twice as much as those in
Rosario?
3. Why did all medical exams have to take place on Wednesday? Is/was
Wednesday a slow-day in the industry?

I hesitate to bring this up on alt.culture.argentina because the replies
will certainly have nothing to do with stamps.

Thanks in advance.

Bienvenidas también respuestas privadas en español (- nogo). Gracias de
antemano.
--
Tony Vella in Ottawa, Canada

remove nogo for reply