PREFACE 



It is the conviction of the writer that the specific objectives of a gen- 

 eral course in Biology for students in colleges of Liberal Arts are 

 three: To impart such principles and concepts as will enable the 

 student to appreciate the unity in Nature and the place of living 

 organisms, including Man, in that unity; to instill an understanding 

 of the major laws that govern living organisms and a recognition of 

 the operation of these laws in determining broad social and eco- 

 nomic controls in human society; to impart useful information and 

 information of such character that a habit of observing caution in 

 the face of all forms of scientific and intellectual quackery will be 

 developed. A fourth objective that is self-evident and which General 

 Biology holds in common with many other academic disciplines is 

 the development of student power of clear and logical reasoning 

 based upon accurate observation and established facts. 



The present volume represents an attempt to collect in succinct 

 form materials which the writer has been employing over many 

 years in his attempts to reach the objectives of a course for non- 

 professional students. He has not failed to take advantage of con- 

 sultation with the more thoughtful students, with the advisors of 

 students, and with other colleagues. Moreover, the writer has had 

 reason to examine with some care the problems involved in the 

 organization of survey and correlation courses and has made a most 

 serious attempt to arrange his subject matter in alignment with such 

 programs. As the writer sees his responsibility, his task has been 

 the clarification of principles that are abstruse, not their elimination. 

 The probable needs of the student in the years after college have 



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