Ron wrote:
I can't find the circuit breakers for any of the upstair bedrooms in
this old, 1908 built house. Would it be reasonably safe to replace a
light switch wearing rubber gloves and rubber-soled shoes if it comes
down to having nno other options?

Replacing the switch "hot" is a very risky proposition, as others have
pointed out. The first order of business should be to find the
disconnect means and overcurrent protection. Start your search at the
meter and work your way outward from there. Every homeowner and tenant
should know where the protective devices are.