CELLULAR TOXINS. 



CHAPTER I. 



THE ETIOLOGY OF THE BACTERIAL DISEASES. 



The bodies of the higher animals are made up of groups of spe- 

 cialized cells, which are mutually dependent, one upon the other, for 

 their normal development and continued healthy existence. These 

 groups of cells constitute the various organs and the framework by 

 which they are held together and through which food is distributed 

 to all, and the special products of one colony are carried to the others, 

 or cast out from the whole as waste material. Each organ has its 

 special functions, the healthy performance of which is necessary to 

 the well-being of the whole. If the digestive cells of the alimentary 

 canal fail to secrete active fluids, the cells of the brain, the heart, 

 the lungs, and, in short, of every part of the body are impaired and 

 disease results. If the food be properly digested and the absorption 

 cells of the walls of the alimentary canal fail, a like disaster is 

 brought upon the whole. If the kidneys, liver, skin, or lungs do 

 not properly eliminate effete and poisonous products, these accumu- 

 late and interrupt the healthy activity of the cells of the body. 

 Disease is the result of impaired or perverted cell action. 



The animal body is often invaded by foreign cells, which may be- 

 come, for a time at least, parasites, living at the expense of the host 

 and elaborating their own special products, which may prove harmful 

 to one or more of the colonies of cells constituting the healthy body, 

 and thus the health, and even the existence of the whole, may be 

 placed in jeopardy. These foreign cells find their way into the body 

 with the food, drink, inhaled air, or through some break in the skin 

 or mucous membrane. The harmful invaders may consist of micro- 

 scopical, unicellular forms of vegetable life known as bacteria, and 

 the action of their special products upon the cells of the body gives 

 rise to the bacterial diseases. 



Certain other vegetable forms of life, especially those belonging 

 to the fungi, may live as parasites on the higher animals. These are 

 not known to produce chemical poisons, but by their presence and 

 encroachment on certain tissues they induce impaired or perverted 

 action of the cells of the same. The skm is the favorite habitat of 

 these parasites, and the disorders which they cause are known as 

 fungous diseases. 



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