30 GOOD HEALTH 



and perhaps they, in turn, seem to him quite too small 

 to notice ; or it may be that he is so much bigger than 

 they are that it is as hard for him to see them as it is for us 

 to see him. Whatever the case may be, and though they 

 are so very small, still we know that some of them can do 

 more harm than mad dogs, while others are more danger- 

 ous than whole armies of soldiers in the enemy's country. 

 They are around us everywhere, in the air we breathe, 

 in the water we drink, in the food we eat. At the same 



time they are of so many 

 shapes and kinds that hun- 



! 



dreds of men study them 



d yv ' f i^ 



* from one year's end to the 



FORMS OF BACTERIA ,, -, , r 



other and learn strange facts 



a, grippe ; b, bubonic plague ; c, diphtheria; 



if, tuberculosis; *, typhoid fever; about them. They also give 



^ spiral types ' them different names, the 



yeast plant, the mold, and the bacteria. Some people 

 speak of them all as germs, but the name that fits every 

 kind best is microbe, meaning " small life." 



Most microbes do us neither harm nor good. Multi- 

 tudes of them are indeed the best friends we have, 

 yet very many others are our worst enemies. It is 

 the microbe that spoils our meat and sours our milk 

 and gives us moldy bread. They rot the fruit after it 

 is picked, and turn sweet grape juice into -wine and 

 vinegar. In all this they are so successful that we might 

 call a piece of spoiled meat or fruit a microbe city, 



