12 PHYSIOLOGY AND TEMPERANCE. 



the tissue; subsequently it is only needed to maintain the 

 body, to make repairs and to supply heat. The human body 

 may be likened to a building, composed of many parts, of 

 different forms, size, density and durability. Together they 

 constitute a perfect structure, harmonious in every part. But 

 one or more of these pieces decay, and to retain the integrity 

 of the structure, repair is made by substituting a sound piece 

 for the one decayed or worn out. Thus repair of a building 

 may be effected by a competent builder, even to replacing the 

 foundation stone. In this manner repair is constantly taking 

 place in the living body. It is a work of nature, and is 

 carried on by wise laws and with unerring precision. 



10. Digestion. The source of supply for repairing the 

 tissues of the body is the food which we eat. To convert the 

 food into blood, the body is provided with the digestive system, 

 consisting of the mouth, teeth, tongue, oesophagus or gullet, 

 stomach, and the intestines. Each of these organs is placed 

 in a position most convenient to serve its purposes. In con- 

 nection with the digestive system are a number of glands, to 

 secrete fluids required in the process of digestion. First, the 

 salivary glands, which discharge the saliva into the mouth, to 

 be mixed with the food as it is ground up by the teeth. After 

 this first step in the process of digestion, the food passes along 

 the gullet to the stomach, where it is churned up, and at the 

 same time mixed with the gastric juice, secreted by glands 

 placed in the coats of the stomach. The greyish pulpy mass 

 thus produced, called chyme, passes into the intestines, to 

 undergo further changes from the action of the intestinal 

 juice, the bile from the liver and the fluid secreted by 

 the pancreas. The chemical and vital changes which have 

 now taken place have prepared the aliment to mix with the 

 blood, and the chyle, as it is now called, is taken up by a 

 system of absorbent vessels and passes by a duct called the 

 thoracic duct, to be emptied into the great volume of blood 



