vi CONTENTS 



PERIOD IV (1790-1858) - 89 



Characteristics of the period. Sprengel and the 

 fertilisation of flowers. Cuvier and the rise of 

 palaeontology. Chamisso on the alternation of 

 generations in Salpa. Baer and the development of 

 animals. The cell-theory. The scientific investiga- 

 tion of the hig-her cryptogams. The enrichment of 

 English gardens. Humboldt as a traveller and a 

 biologist. Premonitions of a biological theory of 

 evolution. 



PERIOD V (1859 AND LATER) - - 124 



Darwin on the Origin of Species. Pasteur's experi- 

 mental study of microbes. 



CHRONOLOGICAL TABLE - - - - - 141 



THE SUB-DIVISIONS OF BIOLOGY - - - 146 



BIBLIOGRAPHY - - - - - 147 



INDEX- - - - - 149 



