This optical trick lithograph depicts a horror stricken mother and her boy in front of a microscope. The image shows the myriad microbial inhabitants of a drop of water, apparently from the Thames river (England), projected in front of them when the print is illuminated from the back. This hidden image sarcastically comments on the state of drinking water in London. Spooner's print is referring to the "scientific" shows popular in London at the time where enterprising charlatans enlarged samples of the Thames water with a projected solar microscope image and then profitably sold their version of "snake oil" to combat the diseases that may be caused by it.
