INTRODUCTORY 



WHAT IS BIOLOGY ? 



While everyone recognises that Biology is Life-science, this is but 

 a translation, not a definition. In its original and best usage, Biology 

 means an inquiry into the nature, continuance, and evolution of 

 living creatures. It does not, indeed, seek to describe all kinds of 

 organisms, for that is the task of its main sub-sciences — Botany 

 and Zoology, with Protistology and Bacteriology; and many claim 

 Anthropology as well ; it deals rather with the problems and general- 

 isations that are common to all living creatures, and on which each 

 line of specialism throws its particular light. 



In a classification of the sciences it is convenient to use the term 

 Biology to include all the biological sciences, as contrasted with 

 chemistry and physics on the one hand, psychology and sociology 

 on the other; but the stricter usage — which began, about 1801, with 

 Treviranus and Lamarck, by whom the word was independently 

 proposed — keeps the term for the study of the general questions that 

 apply to all forms and processes of organisms. What is the nature of 

 that particular kind of activity that we call "Life"; how does the 

 individual organism begin and develop; how does it persist from 

 day to day and continue its kind, sometimes in slightly changed 

 expression, from generation to generation? It is in this sense that 

 the word Biology is used in this book. 



A third and indefensible usage, common in Germany, is as an 

 equivalent for Ecology, or the study of habits and inter-relations. 

 Sometimes, however, it is convenient to speak of "The Biology of 

 Birds", or "The Biology of Insects", or the like, to denote a book 

 or treatise that deals with a particular class or type in such a way 

 as to illustrate and contribute to General Biology. 



A scientifically inquisitive mind — such as we hope our reader's is — 

 is often inclined to begin a biological inquiry with the question: 

 What is Life? But this is obviously not a beginner's question; it is 

 more likely to be answered, and then but tentatively, towards the 

 end of our studies. So in this book let us begin not with "Life", but 

 with a concrete and descriptive study of the characteristics of 

 living organisms, and with glimpses of the life-drama in which they 

 play their part. The first step is to fill the mind with vivid impres- 

 sions of organisms as active agencies, prompted by hunger and love 

 and the will to live, seeking more life in their developing, growing, 

 and multiplying, and rarely ceasing to be insurgent against environ- 

 ing difficulties and limitations. Life may be traced down into par- 



VOL. I B ' 



