Sentence:  And as it commonly happens, that when the Stag begins to be <WSD>embost</WSD>, and finds his strength to faile-him, having no other remedie left him, doth yeeld and bequeath himselfe unto us that pursue him, with teares suing to us for mercienb.... 
Meaning of the word marked with <WSD> tags:  To drive (an animal) to extremity; to exhaust, to make foam at the mouth.