4 BIOLOGY AND ITS MAKERS 



As a result of these advances, animal organization began 

 to have a different meaning to the more discerning naturalists, 

 those whose discoveries began to influence the trend of 

 thought, and fmally, the idea which had been so often pre- 

 viously expressed became a settled conviction, that all the 

 higher forms of life are derived from simpler ones by a gradual 

 process of modification. 



Besides great progress in biology, the nineteenth century 

 was remarkable for similar advances in physics and chem- 

 istry. Although these subjects purport to deal with inorganic 

 or lifeless nature, they touch biology in an intimate way. 

 The vital processes which take place in all animals and plants 

 have been shown to be physico-chemical, and, as a conse- 

 quence, one must go to both physics and chemistr}' in order 

 to understand them. The study of organic chemistry in late 

 years has greatly influenced biology; not only have living 

 products been analyzed, but some of them have already been 

 constructed in the chemical laboratory. The formation of 

 living matter through chemical means is still far from the 

 thought of most chemists, but very complex organic com- 

 pounds, which were formerly known only as the result of 

 the action of life, have been produced, and the possibilities 

 of further advances in that direction are very alluring. It 

 thus appears that the discoveries in various fields ha\e 

 worked together for a better comprehension of nature. 



The Domain of Biology. — The history of the transforma- 

 tion of opinion in reference to living organisms is an inter- 

 esting part of the story of intellectual development. TIk 

 central subject that embraces it all is biolog}-. This is one 

 of the fundamental sciences, since it embraces all questions 

 relating to life in its different j)hases and manifestations. 

 Everything pertaining to the structure, the development, and 

 the evolution of living organisms, as well as to their physiol- 

 og}', belongs to biology. It is now of commanding impor- 



