Are the eminent representatives of this science really the materialists and monists they would have to be, if all this were true? The foremost physiologist of the nineteenth century was _J. Müller_ (died 1858), buried in the Catholic cemetery at Berlin. He was a decided opponent of materialism; he not only contended for the existence of a spiritual soul, but also for an immaterial vital force in plants. _Th. Schwann_ (died 1882) is the founder of the cellular theory. In the year 1839 he accepted a call to take the chair of anatomy at the Catholic University of Louvain. One of the most prominent physiologists of the nineteenth century was _A. Volkmann_ (died 1877). He was a stout champion of the spirituality and immortality of the soul, of purposive cause in animated beings, and an opponent of _Darwin’s_ theory. _G. J. Mendel_ (died 1884) became by his work on _Experimenting with Hybrid Plants_ the pioneer of the modern theory of hereditary transmission, adopted by modern biology; and scientists like _H. de Vries_, _Correns_, _Tschermak_, and _Bateson_ followed his lead. “His important laws of hereditary transmission are the best so far offered by the research in this field” (_Muckermann_, Grundriss der Biologie). He was a Catholic priest, and the abbot of the Augustinian Monastery at Old-Brünn. _Karl von Vierordt_ (died 1884) is well known by his “Manual of Physiology,” still in demand as a reference book in the libraries of universities. In 1865 he delivered a speech at the Tübingen University on the unity of science, concluding with this appeal to the students: “Until your religious notions become clear by a mature insight, trust in the well-meant assurance that the belief in the divinity of the religion of Jesus has not been put falsely into your heart. True piety is equally remote from narrow pietism as from freethinking indifference; it leaves to reason its full rights, but it also assures to us the faculty to be aware, in joyful confidence in Almighty Providence, of an immaterial and for us eternal destiny.” _Ch. Ehrenberg_ (died 1876) is the explorer of the world of little things: of infusoria and protozoa. He did not countenance _Haeckel’s_ materialism nor _Darwin’s_ denial of teleology: to him they were fantastic theories and romances. A friend of his, and of the same mind, was _K. von Martius_, who admired God’s wisdom in the wonders of the world of vegetation. Long before his death he ordered his burial dress to be made of white cloth embroidered with a green cross,—“a cross because I am a Christian, and green in honour of botany.” Another renowned name may be mentioned, that of the Austrian anatomist _J. Hyrtl_ (died 1894).