BACTERIA IN FOOD 119 



is filled with them ; sour milk contains them in immense 

 numbers ; moldy bread and bad eggs hold millions of them, 

 and decaying fruit may show bacteria as well as molds. 

 All types of food which develop peculiar taints and tastes 

 characteristic of putrefaction contain great numbers of 

 bacteria. Long before these taints are appreciable to 

 the senses the bacteria that produce them are abundant. 

 No moist food can be exposed on pantry shelves or in 

 ice chests, even for an hour, without containing bacteria, 

 and after it has remained there for 

 a day or two the number of bac- 

 teria present in it becomes very 

 great indeed, because of the multi- 

 plication of those that have found 

 entrance. 



In the Body. The presence of 

 bacteria in food leads us to expect F IG - 5 8 - Bacteria from the 

 to find them in our mouths, stom- teeth of a health ? mouth ' 

 achs, and intestines. Our whole digestive tract is crowded 

 with them. Fig. 58 represents a bit of the scrapings from 

 the teeth, highly magnified, and containing hundreds of 

 several different species of bacteria. They are equally or 

 more abundant in the stomach and intestines. This is 

 the normal condition of things, and these bacteria do us 

 no injury, but are probably of direct use. 



The substance of the matter is that bacteria are practi- 

 cally everywhere on the surface of the earth. They are 

 in immense numbers in the household, on the walls and 

 ceilings of our rooms, upon our pantry shelves ; they 

 are present in every bit of food which remains exposed 

 to the air for a short time ; they are in all liquid foods, 



