Steno, Nicolaus

( Lat ), Niels Steensen ( Dan ) [ stee noh] (1638–86) Danish anatomist and geologist: made early studies of crystals and fossils.

An anatomist by training, Steno was also interested in crystals and fossils. He showed that a pineal gland like that of man is found in other animals, and used this and other arguments to refute claim that it is the seat of the soul and uniquely human. His study of quartz crystals revealed that, although the shapes varied, the angle between corresponding faces is fixed for a particular mineral. This constancy, sometimes called Steno’s Law, is a consequence of the internal ordering of the constituent molecules in the crystal. Steno also accepted the organic nature of fossils and recognized that sedimentary strata were laid down in former seas, having found fossil teeth far inland that closely resembled those of a shark that he had dissected. His geological sections were probably the first to be drawn.

He became a priest in 1675, was ordained a bishop in 1677 and gave up science thereafter.