You see that some of the yeast plants and bacteria

You see that some of the yeast plants and bacteria

You see that some of the yeast plants and bacteria

You see that some of the yeast plants and bacteria, as many of these forms are called, are very friendly to us, while others do us great harm.

Some bacteria grow within the bodies of men and other animals or in plants. When they do so they may produce disease. Typhoid fever, diphtheria, consumption, and many other serious diseases are caused by bacteria. Fig. 118, e, shows the bacterium that causes typhoid fever. In the picture, of course, it is very greatly magnified. In reality these bacteria are so small that about twenty-five thousand of them side by side would extend only one inch. These small beings produce their great effects by very rapid multiplication and by giving off powerful poisons.