GERMS. 49 



the different germs are found in the different diseases 

 because of the different variety of nourishment pro- 

 vided. This nourishment may be the accumulation in 

 the system of natural waste products, or may include 

 tissue that has been destroyed by disease. Through 

 the circulation the same kind of food is carried to the 

 different cells of which the body is formed. But the 

 cells do not admit all kinds of nourishment. They 

 exhibit a marked selective power, hence muscle-cells 

 are formed of one kind of matter, bone-cells of an- 

 other, liver-cells of another, and those of the central 

 nervous system another, etc. Muscle-cells have the 

 power of expension and contraction, giving the power 

 of motion. Bone-cells are two-thirds lime salts, giv- 

 ing solidity to the framework. Bone is said to be 

 twice as strong as oak. The liver-cells manufacture 

 bile, which aids digestion, while the brain-cells are the 

 seat of reason, judgment, memory, emotion, sensation, 

 pleasure, pain and all that we see, hear, enjoy or suffer. 



Why this difference ? Because each cell absorbs dif- 

 ferent nourishment. It is necessary that the different 

 cells select different food-elements because of their 

 several duties, hence their selective power. It is also 

 necessary that other cells called germs select different 

 food-elements, because of their several duties. Some 

 germs find such elements in diseased brain or liver tis- 

 sue as in brain-disease or liver-abscess; some in dead 

 and dying lung-tissue, as in grip, pneumonia, bronchitis 

 or consumption, and some in a diseased digestive tract, 

 as in typhoid fever. 



As just mentioned, these different organs and tissues 



