1791. Galvani's experiments on animal electricity. 1792. Sprengel's _Entdeckte Geheimniss der Natur_. F. Huber's _Nouvelles Observations sur les Abeilles_. 1796. Cuvier on recent and fossil elephants. 1798. Jenner's _Inquiry_ (vaccination against small-pox). Lithography invented by Senefelder. 1799. William Smith's _Order of the Strata and their Embedded Organic Remains_. 1799-1825. Laplace's _Mécanique Celeste_. 1800. Volta's electric pile. 1807. Dalton's Atomic theory. Davy's decomposition of potash and soda. 1811. Motor and sensory roots of spinal nerves discovered by Bell. 1812. Cuvier's _Ossemens Fossiles_. 1816. Cuvier's _Règne Animal_. 1819. Electro-magnetism discovered by Œrsted. Chamisso's _De Salpa_. 1823-1831. Pollen-tubes traced to the ovule (Amici, Brongniart, Robert Brown). 1827. Discovery of mammalian ovum by Baer. 1828-1837. Baer's _Entwickelungs-geschichte_. 1830-1832. Lyell's _Principles of Geology_. 1835. Cell-division in plants observed by Mohl. 1837. Caignard-Latour's demonstration that alcoholic fermentation is due to living organisms. 1839. Schwann and Schleiden's cell-theory. 1840-1849. Joule's determination of the mechanical equivalent of heat. 1841. Faraday's discovery of electric induction. 1846. Discovery of Neptune by Leverrier and Adams. Agassiz and Buckland's announcement of extensive glaciation in Scotland. 1848. Discovery of the antheridia of ferns by Suminsky. 1849-151. Hofmeister's comparative studies of the higher cryptogams and the flowering plants. 1809-1851. Charles Darwin. 1822-1895. Louis Pasteur. THE SUB-DIVISIONS OF BIOLOGY Morphology: Anatomy. Minute Anatomy. Comparative Anatomy. Embryology. Physiology (including adaptations to the conditions of life). Psychology of Animals. Classification. Geographical Distribution. Palæontology. All these divisions, except Psychology, apply both to plants and animals. Many other modes of division have been proposed. BIBLIOGRAPHY [It will be readily understood that the literature of Biology is enormous, as a single fact will show. Half a century ago Dr. Hagen compiled a list of books and papers relating to Entomology alone. Though far from complete, it filled a thousand pages, and if brought down to the present date would probably fill a thousand more. The student who tries to follow in some detail the history of any branch of Biology must read books in half-a-dozen languages, and work continually in large public libraries. We shall attempt no more in this place than to mention a few books which can be procured and read by those whose leisure and knowledge of the subject are limited.] History of Biology or its Sub-Divisions. Carus, V. _Geschichte der Zoologie_. 1864 foll. The French translation by Hagenmuller and Schneider (1880) will be preferred by some.