The famous collection of the Dutch anatomist Ruysch has always been the pride of the Kunstkammer. Peter I saw it for the first time during the days of the Great Embassy. Ruysch became famous for his unique way of making injections: by injecting a colored thickening solution into the blood vessels of a human body he could observe even the smallest branches of blood vessels in various organs. The anatomist remained an unsurpassed master of the «art of Ruysch» not only during his life, but even in death. He took his unique secret of embalming corpses of adults and children to his grave; and he had dissected them so skillfully that they looked alive. Ruysch kept his artifacts dry or in glass jars, bathing them with an alcohol solution made from black pepper. To make them look cheerful and natural, he decorated them with beads, artificial flowers and lacy garments. Contemporaries regarded them with admiration and considered his articles the eighth wonder of the world. Ruysch arranged his collections according to the traditional allegorical method. His collections demonstrated the popular idea of vanity and the fleeting nature of human life. He believed that «death is an act of grace, given to us by the divine Lord».
After the famous decree of Peter I, passed on February 13, 1718, on gathering monsters, dozens of them, both living and dead, began to arrive at the Kunstkammer. Teratology, i.e. the science of freaks and monsters, was considered not only amusing, but highly useful: it helped to prove that freaks were born into this world without any diabolic interference, but due to natural causes. Monsters were much appreciated, and since attempts to hide them were punished by a considerable fine, they were brought to the Kunstkammer in abundance. They were dissected in the anatomical theater of the Kunstkammer, and them placed on display.
«Human and animal freaks» were collected by order of Peter I in all parts of Russia, since «all of them should be gathered as curiosities». Some of them, like this stuffed double-headed calf, are still preserved in the museum’s collections.