The "dream city" of Jena, p. 145--The old market-place, p. 147--The old lecture-halls of the university, p. 148--Ernst Haeckel, p. 151--His discoveries of numerous species of radiolarians, p. 153--The part played in evolution by radiolarians, p. 156--Haeckel's work on morphology, and its aid to Darwinian philosophy, p. 156--Freedom of thought and expression in the University of Jena, p. 157--Haeckel's laboratory, p. 160--His method of working, p. 161--His methods of teaching, p. 164--The import of the study of zoology, p. 166--Its bearing upon evolution, p. 168--The present status of Haeckel's genealogical tree regarding the ancestry of man, p. 171--Dubois's discovery of the skull of the ape-man of Java, p. 173--Its close resemblance to the skull of the ape, p. 173--Man's line of descent clearly traced by Haeckel, p. 175--The "missing link" no longer missing, p. 176. CHAPTER VII--SOME MEDICAL LABORATORIES AND MEDICAL PROBLEMS The Boulevard Pasteur, p. 179--The Pasteur Institute, p. 180--The tomb of Pasteur within the walls, p. 181--Aims and objects of the Pasteur Institute, p. 182--Antirabic treatment given, p. 183--Methods of teaching in the institute, p. 185--The director of the institute and his associates, p. 185--The Virchow Institute of Pathology, p. 186--Studies of the causes of diseases, p. 187--Organic action and studies of cellular activities, p. 188--The discoveries of Rudolph Virchow, p. 188--His work in pathology, p. 189--Character of the man, his ways of living and working, p. 189--His methods of lecturing and teaching, p. 191--The Berlin Institute of Hygiene, p. 193--Work of Professor Koch as carried on in the institute, p. 194--Work of his successors in the institute, p. 195--Investigations in hygiene, p. 196--Investigations of the functions of the human body in their relations to everyday environment, p. 197--The Museum of Hygiene, p. 198--Studies in methods of constructing sewerage systems in large cities, p. 199--Studies in problems of ventilation, p. 200. CHAPTER VIII--SOME UNSOLVED SCIENTIFIC PROBLEMS