AMEBICAN JOUKNAL OF SCIENCE 19 



In geology, vast progress has been made in the 

 knowledge of the earth, not only as to its features now 

 exhibited at or near the surface, but also as to its history 

 in past ages, of the development of its structure, the 

 minute history of its life, the phenomena of its earth- 

 quakes, volcanoes, etc. Geological surveys in all civilized 

 countries have been carried to a high degree of per- 

 fection. 



In biology, itself a word which though used by 

 Lamarck did not come into use till taken up by Huxley, 

 and then by Herbert Spencer in the middle of the cen- 

 tury, the progress is no less remarkable as is well devel- 

 oped in a later chapter of this volume. 



Although not falling within our sphere, it would be 

 wrong, too, not to recognize also the growth of medicine, 

 especially through the knowledge of bacteria and their 

 functions, and of disease germs and the methods of com- 

 bating them. The world can never forget the debt it 

 owes to Pasteur and Lister and many later investigators 

 in this field. 



To follow out this subject further would be to encroach 

 upon the field of the chapters following, but, more 

 important and fundamental still than all the facts dis- 

 covered and the phenomena investigated has been the 

 establishment of certain broad scientific principles which 

 have revolutionized modern thought and shown the rela- 

 tion between sciences seemingly independent. The law 

 of conservation of energy in the physical world and the 

 principle of material and organic evolution may well be 

 said to be the greatest generalizations of the human 

 mind. Although suggestions in regard to them, particu- 

 larly the latter, are to be found in the writings of early 

 authors, the establishment and general acceptance of 

 these principles belong properly to the middle of the 

 nineteenth century. They stand as the crowning achieve- 

 ment of the scientific thought of the period in which we 

 are interested. 



Any mere enumeration of the vast fund of knowledge 

 accumulated by the efforts of man through observation 

 and experiment in the period in which we are interested 

 would be a dry summary, and yet would give some meas- 

 ure of what this marvelous period has accomplished. As 



