4 HUMAN PHYSIOLOGY CHAP. 



We shall learn something of public health or of the 

 laws that relate to the well-being of people living in 

 towns, villages, and cities. There are laws of public 

 health as well as of personal hygiene. 



6. The Amoeba. In water and moist earth there live 

 animals so small that they can be seen only with the aid 

 of a microscope. The amoeba belongs to one of these 

 classes. It looks when highly magnified like a bit of 

 jelly. No one who does not watch it closely for a long 

 time would believe that it is a live animal. It is so 

 simple in structure that it is without mouth, head, legs, 

 or stomach, and yet it has the power to move about in 



FIG. i. Amoebas as seen under the microscope (Buchholz). 



the water, to breathe, and to eat. When the amoeba 

 has grown to full size it divides and forms two tiny 

 amoebas, each having all the power of the parent. The 

 amoeba is a tiny bit of living matter called protoplasm. 



Place under the microscope a drop of water taken from a stagnant 

 pond, or from a barrel of rain water that has become somewhat slimy.. 

 Examine it very carefully for amoebas. Make a drawing of what you 

 see. 



7. The Cell. Our bodies are very complex in 

 structure, being made up of numerous parts or organs 

 which do not look at all alike. Each of these parts is 

 composed of many small bits of living matter called 



