more profound and comprehensive views on nature which gave a new direction to observation were at this time enunciated.
This movement manifested itself, for instance, in the domain of mineralogy. Gadolin, who perceived very clearly the value of mathematical formulae and geometrical figures in order to express the laws which regulate the symmetry of crystals, put forward the hypothesis of a homogeneous crystalline substance enclosed in them. Gadolin's work was continued and improved by Fedorov: he elaborated a vast scheme of all possible structures of crystals. Vernadsky studied, not only crystallography, but some of the physico- and geo-chemical processes in minerals and began to describe their types in a systematic survey.
Progress was made also in anatomy and physiology: Pirogov, the celebrated pupil of the Dutchman, Moier of Dorpat, made an important contribution to the development of anatomy: he anticipated the bacteriological theory of blood-putrefaction and used anaesthetics in surgical operations which were further improved by Gruber; Yakubovich, and, somewhat later, Bechterev made acute microscopical investigations concerning the anatomy of the nervous system; meanwhile Syetchenov became famous for his physiological researches, particularly on the cerebro-spinal reflexes, while Pavlov elaborated a lucid conception of the reciprocal action of the organs which play a part in the normal life of the body, and began his celebrated experiments on the circulation of blood, the secretory functions of the digestive glands, and the reflexes of the brain.
More complicated and concrete sciences, such as
