Natural history had a parallel development with comparative anatomy, 110. The Physiologus, or sacred natural history of the Middle Ages, 110, 111. The lowest level reached by zoölogy, 111. The return to the science of Aristotle a real advance over the Physiologus, 112. The advance due to Wotton in 1552, 112. Gesner, 1516-1565. High quality of his _Historia Animalium_, 112-114. The scientific writings of Jonson and Aldrovandi, 114. John Ray the forerunner of Linnæus, 115. His writings, 117. Ray's idea of species, 117. Linnæus or Linné, 118. A unique service to natural history. Brings the binomial nomenclature into general use, 118. Personal history, 119. Quality of his mind, 120. His early struggles with poverty, 120. Gets his degree in Holland, 121. Publication of the _Systema Naturæ_ in 1735, 121. Return to Sweden, 123. Success as a university professor in Upsala, 123. Personal appearance, 125. His influence on natural history, 125. His especial service, 126. His idea of species, 128. Summary, 129. Reform of the Linnæan system, 130-138. The necessity of reform, 130. The scale of being, 131. Lamarck the first to use a genealogical tree, 132. Cuvier's four branches, 132. Alterations by Von Siebold and Leuckart, 134-137. Tabular view of classifications, 138. General biological progress from Linnæus to Darwin. Although details were multiplied, progress was by a series of steps, 138. Analysis of animals proceeded from the organism to organs, from organs to tissues, from tissues to cells, the elementary parts, and finally to protoplasm, 139-140. The physiological side had a parallel development, 140. CHAPTER VII Cuvier and the Rise of Comparative Anatomy, 141 The study of internal structure of living beings, at first merely descriptive, becomes comparative, 141. Belon, 141. Severinus writes the first book devoted to comparative anatomy in 1645, 143. The anatomical studies of Camper, 143. John Hunter, 144. Personal characteristics, 145. His contribution to progress, 146. Vicq d'Azyr the greatest comparative anatomist before Cuvier, 146-148. Cuvier makes a comprehensive study of the structure of animals, 148. His birth and early education, 149. Life at the sea shore, 150. Six years of quiet study and contemplation lays the foundation of his scientific career, 150. Goes to Paris, 151. His physiognomy, 152. Comprehensiveness of his mind, 154. Founder of comparative anatomy, 155. His domestic life, 155. Some shortcomings, 156. His break with early friends, 156. Estimate of George Bancroft, 156. Cuvier's successors: Milne-Edwards, 157; Lacaze-Duthiers, 157; Richard Owen, 158; Oken, 160; J. Fr. Meckel, 162; Rathke, 163; J. Müller, 163; Karl Gegenbaur, 164; E.D. Cope, 165. Comparative anatomy a rich subject, 165. It is now becoming experimental, 165. CHAPTER VIII