The ghost of a flea?

Of all the images William Blake produced, the strangest and most appealing to me is The Ghost of a Flea (1820). It’s on display at Tate Britain: a small, dark, oddly menacing object, tempera and gold on wood. As this short Atlas Obscura article recalls, Blake claimed the ‘ghost’ itself came to him in one of his visions and “posed for him as he sketched it. He was able to ‘communicate’ with the monstrous being, who revealed that all fleas were inhabited by the souls of men who were ‘by nature bloodthirsty to excess.'”
Did Blake actually see or simply ‘imagine’ his visions? Or maybe he was inspired by images of fleas from the scientist Robert Hooke’s book Microphagia. 150 years before Blake’s flea, Hooke “produced illustrations based on his pioneering documentation of organisms as seen through microscopes. The march of science was gradually revealing hitherto unknown, invisible, and unsettling worlds that sparked fears about what else could exist undetected beyond the boundaries of the human senses.”
Blake opposed what he saw as science’s dominating ‘singular vision’ reducing our understanding of the world. But it’s intriguing to think of him drawing on science’s own efforts to render the invisible visible.
.