St. Jerome

Recently I came across a cast-off book about the history of windows. Upon opening the book, and looking at the engraved frontispiece, what do I see ? **gasp*!

What do you notice?  Yeah, ME too!  The gourd hanging in the upper right-hand corner!  In this detailed 1514 illustration by Albrecht Durer. This work is packed with symbolism, but I cannot locate any source that picks out the symbolism for the gourd.