PRINCIPLES OF ANIMAL BIOLOGY 



CHAPTER 1 

 THE GROWTH AND SCOPE OF BIOLOGY 



When knowledge can be classified and organized on some basis 

 which exists in nature, not just in the minds of men, the body of knowl- 

 edge so arranged is science, or a science if the field is limited. The devotees 

 of science seek to discover the natural principles which control the 

 phenomena they observe. The more fundamental the ascertained 

 principles are, the more significant the science is. The first step in dis- 

 covering principles is usually observation of the facts or phenomena 

 which require explanation. Very often the second step is experiment, 

 or interference with natural events, with possible alternative outcomes 

 in mind. Finally, there is the logical consideration of all facts to see 

 what relation exists among them. 



When the phenomena studied are those of living things, the organized 

 knowledge is called biology. It is not distinct and separate from other 

 sciences, for all life processes are fundamentally physical and chemical. 

 Indeed, no science is a province unto itself, for the constitution of matter 

 and energy, with which they all deal, is everywhere the same. Each 

 division of the field of science emphasizes certain types of phenomena, 

 but the more the various fields can be intertwined the more fruitful 

 scientific work becomes. 



The several sciences have also been interrelated as they developed 

 over the centuries. Let us see how biology has shared in the early stages 

 of this growth and what it has come to be in later times. 



Ancient Civilizations. — Among primitive peoples knowledge and 

 superstition regarding life came chiefly from three sources: from their 

 wonder and awe at the phenomenon of death and customs relating to 

 the preservation of the bodies of the dead, from their fear of the great 

 wild beasts, and from their attempts to cure disease and heal injury. 

 The earliest known civilization is that of Babylon. Medical science, 

 which is the form that early biology most often took, made some progress 

 there. Clay models of various organs of the human body have been 

 preserved, and Babylonian writings show that two kinds of blood, light 

 and dark, were recognized. The heart, however, was regarded as the 

 seat of intelligence. In Egypt, another very old civilized country, 



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