background removal - How to remove a specific color in an image in Photoshop?

I am not an expert photoshop user but have been trying to use more of it in what I currently do.

I have a black and white image from which I am trying to remove all the white.

I cannot use the magic wand/delete because the white is in literally hundreds of places and in some cases very tiny.

Is there a method to strip the white off, leaving just the black?

Thanks in advance for your help.