Descartes: ".. To seek the truth of [nature] the sciences "(Discours de la méthode.., Leyden 1637) described the new philosophical and scientific spirit in the Europe of 1600. Niels Stensen, born in Copenhagen in 1638, studied medicine at the university on the basis of classical language and culture and met the modern currents through the literature until he in 1659 received support for a study trip in the leading western Europe. An excellent school from Copenhagen, developed abilities for observation and analysis and inspiration from like-minded led him to new realization in the field of anatomy, physiology and since the geoscience that aroused admiration in the formed Europe. Stenos language proficiency, sensitivity and tact were no less significant. Sense of reality and sensitivity made him early skeptical of academic pride, such as Descartes's claim that animals have no emotions. They also marked him as a gifted teacher. However, he never got an ordinary university post. The lecture will pay particular attention to the contribution of European stone to the realistic nature perception.