INTRODUCTION 3 



in the body, and the connections of these parts with each 

 other. The anatomy of a lifeless body can be studied far 

 more completely than can the anatomy of a living animal, 

 for any complete knowledge of structure involves dissecting 

 or cutting into the various regions. The term anatomy is 

 derived from two Greek words which mean to cut up, (ana ' = 

 up + tem'nein = to cut). 



Physiology. For the study of physiology, however, a liv- 

 ing organism is necessary, since this science is the study of 

 the uses or functions of the various organs. The functions 

 of a cat's claws can be determined only by watching the use 

 the cat makes of them. Man has found out the use of the 

 internal organs of animals largely by experimenting upon 

 them, and many of the wonderful discoveries in medicine 

 have been made by studying the physiology of dogs, guinea 

 pigs, and other animals. 



Physiology has for most of us a meaning altogether too 

 limited, for we usually confine the term to the study of the 

 human body. We should remember that it includes the con- 

 sideration of the functions not only of all the countless 

 species of animals, but of all forms of plant life as well. And 

 if we could carry our studies far enough, we should see that 

 similar vital processes are performed in the lowest of plants 

 and in the highest of animals, however much these organisms 

 may differ in structure. 



Hygiene. The word hygiene is derived from the Greek 

 word hy-ge'ia, which means health. This branch of science 

 treats of the conditions that tend to develop and maintain 

 a healthy body. It cannot be studied to good advantage 

 until one becomes acquainted with the structure and uses of 

 the various parts of one's body ; it must, therefore, be pre- 

 ceded by some knowledge of anatomy and physiology. 



Biology (Greek bi'os = life + log'os = science) is the gen- 

 eral name given to the study of all living things. Hence 

 this science treats of both animals and plants, and includes 

 a consideration of their anatomy, physiology, and hygiene. 



