4 GEOLOGICAL BIOLOGY. 



with the history of the organisms. It is proposed to examine 

 and note what have been the relations existing between organic 

 form and geological and geographical conditions and progress. 



Investigation of the Laws of Evolution, — Evolution has been 

 discussed and applied in a thousand ways of late years, until 

 the word has become a kind of shibboleth of modern science. 

 It is proposed, in the following chapters, to ascertain what 

 the term really means in the one field in which it may be 

 properly and scientifically applied. For this purpose it is 

 necessary to use the methods of philosophy, as well as those 

 of science ; to weigh the arguments and reasonings of natural- 

 ists, as well as to examine, analyze, and classify the facts of 

 nature. 



Old Notion of an Organism contrasted with the New. — Within 

 the last thirty years very great change has taken place in the 

 general ideas regarding the nature of organisms and their rela- 

 tions to each other. The old idea of an organism perpet- 

 uating its kind by generation, in which difference of kind was 

 at once evidence of difference of origin, has of late been almost 

 entirely replaced by the new idea in which there is not only 

 repetition by generation of the characters of its ancestors, but 

 a constant slight and slow divergence from them, resulting, in 

 the course of many generations, in bringing about all the dif- 

 ferences of form which distinguish the various species of the 

 world, present and past. The new theory has led to an ex- 

 haustive study of the relations which organisms bear to one 

 another and the interrelations existing between geographical 

 and geological conditions on the one hand and the form of 

 organisms on the other. 



Work of the Paleontologist. — While embryologists have been 

 tracing out in detail the changes experienced by the indi- 

 vidual in passing from the embryonic to the adult stage of 

 growth, and while the zoologist and botanist have been mi- 

 nutely examining and teaching the differences in structure 

 and function of the various parts of each animal and plant, 

 the paleontologist has been accumulating data to show the 

 order of succession of life in the past, and thus has been 

 opening the way for the particular study of organisms in their 

 relations to time and space, their geological sequence, their 



