IV PREFACE TO THE FIRST EDITION. 



era! education or may afford a basis for further studies in General 

 Biology, Zoology, Botany, Physiology, or Medicine. 



Believing that biology should follow the example of physics 

 and chemistry in discussing at the outset the fundamental prop- 

 erties of matter and energy, we have devoted the iirst three 

 chapters to an elementary account of living matter and vital en- 

 ergy. In the chapters which follow, these facts are applied by 

 a fairly exhaustive study of a representative animal and plant, of 

 considerable, though not extreme, complexity a method which 

 we believe affords, in a given time, a better knowledge of vital 

 phenomena than can be acquired by more superficial study of a 

 larger number of forms. We are satisfied that the fern and the 

 earthworm are for this purpose the best available organisms, and 

 that their study can be made fruitful and interesting. The last 

 chapter comprises a brief account of the principles and outlines 

 of classification as a guide in subsequent studies. 



After this introductory study the student will be well pre- 

 pared to take up the one-celled organisms, and can pass rapidly 

 over the ground covered by such works as Huxley and Martin's 

 "Practical Biology,' Brooks' s "Handbook of Invertebrate 



O/ ' 



Zoology," Arthur, Barnes and Coulter's "Plant Dissection," or 

 the second part of this book, which is well in hand and will 

 probably be ready in the course of the following year. 



The directions for practical study are intended as suggestions, 

 not substitutes, for individual effort. We have striven to make 

 the work useful as well in the class-room as in the laboratory, 

 and to this end have introduced many illustrations. The gener- 

 osity of a friend has enabled us to enlist the skill of our friend 



t/ 



Mr. James H. Emerton, who has drawn most of the original 

 figures from nature, under our direction. We have also been 

 greatly aided in the preparation of the figures by Mr. William 

 Glaus of Boston. 

 SEPTEMBER, 1886. 



