Human Physiology. 



waves break upon the nerves of hearing. And by means of 

 wonderfully designed and constructed instruments, and nerves, 

 and brain, the sentinel soul within them all hears and sees. 

 But who can doubt that there is a spiritual ear living in the 

 material ear a spiritual eye which has formed and makes use 

 of the wonderful organ of vision ? 



CHAPTER IV. 



THE ALIMENTARY SYSTEM. 



Food Elements Organs of the Oyster Alimentary Canal of an Insect 

 Mucous Membrane Teeth of Herbivorous, Carnivorous, and Frugiv- 

 orous Animals Saliva The Stomach Gastric Juice Small Intes- 

 tines Cilia Pancreas Bile Villi and Follicles Lymphatics 

 Constipation Relations of Food to Health. 



THE bodies of men and all animals are built up, and their 

 wastes repaired, by food, which is digested, or dissolved, 

 reduced to a uniform creamy fluid, and under the influence of 

 nervous action, converted into living blood, and circulated 

 throughout the system. This blood furnishes the matter of 

 bones, muscles, brain, nerves, and every organ and tissue, and 

 continues to supply fresh matter to make up for the waste 

 ordinarily going on in every part of the body. All animals 

 receive food; they all have a circulating fluid blood or its 

 equivalent ; all breathe air, or water containing air, so that the 

 circulating fluid can be purified and vivified by the action of 

 oxygen. 



Even an animal so low down in the scale of being as the 

 oyster has a complex and beautiful organism of digestion, cir- 

 culation, respiration, with a nervous system suited to its mode 

 of existence. 



The animal kingdom depends for its food, the matter of 



N 



