Putting + voltage directly on the base without much current limiting
(resistor in series) will blow the base emitter junction.  The base acts
like a single diode and has 0.7 volts drop.  Thus it will draw almost
the short circuit current of the +12V supply.
Put a 1k resistor in series with the +12V to prevent damage.

Putting - voltage on the base (again without current limiting) will
cause the base emitter junction to act as a zener diode, and also blow
the junction.  The junction should "zener" at about negative 6 - 8
volts?  Check this by putting a 1K in series with the -12V.

If you can put +/- 12V directly on the base with very little current
flow, the base-emitter junction is already blown open.

Transistors are CURRENT operated devices.  The collector to emitter
current is controlled by base to emitter current (Beta=Ic/Ib= 50-400?).
You always have resistors or some way to limit the currents that result
from applying the voltages.

The "Diode" function on a DMM is a good way check to see if you still
have a B-E junction.   Usually the RED lead is + on a DMM?  Reverse the
leads to make sure
there is no reverse conduction.

You can also use the +12V PS with the 1K series resistor and measure the
B-E voltage with the DMM.  Again, flip the voltage around to check the
"Zener" effect.

Transistors are cheap, so that is the good news!

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