CONTENTS. Vll 



CHAPTER X. 



THE BIOLOGY OF AN ANIMAL (continued.) 



PAGE 



General Physiology. The earthworm and the environment. Income. Di- 

 gestion and absorption. Metabolism. Outgo. Comparison of the 

 plant and animal. Practical study of Lumbricus. 161 



CHAPTER XI. 



OUTLINES OF CLASSIFICATION. 



Grouping of living things. Basis of classification. Natural and artificial 

 systems. Correlation of structure. Homology and analogy. Limits 

 of groups in the natural system. Outline of the system. Table show- 

 ing special classification of plants and animals. 173 



APPENDIX. 



Instruments and utensils. 181 



Reagents and technical methods. 181 



Objects for study. 185 



