Etching by G R S of Lieberkuhn (1711-1756). In 1738 Lieberkuhn invented a microscope for illuminating opaque objects. Its principle was based on Fahrenheit's solar microscope, and it had a small, concave, highly polished silver speculum. This enabled the sun's rays to reflect directly on the object being examined. This speculum was later named after him. Lieberkuhn described for the first time the structure and function of the glands attached to the villi, in the intestine. These became known as Lieberkuhnian glands. He also devised special microscopes which enabled fluid motion in living animals to be seen in detail, and to better understand the circulatory vesels.
© Science Museum / Science & Society Picture Library