Ignition coil diode?

[cl4rk2@worldnet.att.net]

On my '69 MGB/GT, I've always been curious about the small electronic
component the PO attaced between the ignition coil (+) terminal and
ground.  It's a small cylinder w/ the following detail:

    (+)  100uF   50WV  | (-)

where  |  is the black band on the negative(-) end of the cylinder.

What is this, and its purpose?  Is it recommended?  One of its leads
broke... should I replace the component w/ the same type?

Kent
'69 MGB/GT