4 PHYSIOLOGY. 



posed of a variety of individual parts, each of which has its own 

 peculiar share of the work to be done and bears an essential relation 

 to the working of the whole. In the watch, the springs, pinions, 

 levers, and numerous little wheels all bear certain relations to one 

 another and assist in the running of the watch. 



Similarly we find that it is characteristic of any living body or 

 organism say, a dog or a rose that it should be made up of a 

 number of different and distinct parts which are so constructed that 

 they may assist in the life of the whole organism. The animal has a 

 head, a trunk, limbs, eyes, ears, etc., externally; heart, lungs, liver, 

 stomach, intestines,- brain, etc., internally. To these parts the name 

 organs has been applied. Thus, the organism is composed of distinct 

 parts called organs. The division of the body into organs is 

 purely artificial. 



An organ is a particular part of the organism that has a certain 

 specified work to do. For example, the liver is a certain structure 

 found in a particular situation in the animal and has assigned as its 

 share of the work of the general economy, the manufacture of the 

 bile to aid digestion. So, also, the eye and the stomach are organs. 

 They are particular parts of the organism concerned in particular 

 work; the eye, in sight, or vision; the stomach, in digestion. 



The work that any organ does is called its function. Since the 

 appearance and structure of the various organs of a living body are so 

 varied, therefore we do not expect that their functions are any more 

 the same than the functions of the watch and locomotive. Thus, the 

 function of the heart is to pump the blood to all parts of the body ; 

 of the blood, to carry nutritious foods to all parts, and at the same 

 time to carry away certain waste-products ; of the kidneys, to excrete 

 waste-matters from the blood ; of the brain, to have a general over- 

 sight and to govern the functions of the whole organism, etc. 



Anatomy is the forerunner of physiology and must pave the way 

 for it. For how are we to study the functions of the various organs 

 and their relations to one another, unless we are acquainted with the 

 structure, form, and position in the body of the various organs? 

 Even while studying physiology, anatomy must run hand in hand 

 with it, particularly that modified form of anatomy histology, or 

 microscopical anatomy which deals with the minute structures and 

 their components the cells. 



We have learned that the various portions of the living body are 

 called organs. As we know, each organ has its own particular work 

 to do. By careful dissection, we find that an organ a human arm, 



