SECTION IV — BACTERIA 



CHAPTER X 



THE GENERAL NATURE OF BACTERIA 



Our study of bacteria must be more extended than that 

 which we have given to either molds or yeasts. While 

 molds and yeasts are of significance in the household, the 

 action of bacteria is much more fundamental and universal. 



Bacteria are far smaller 

 than yeasts or molds 

 (Fig. 46). Some house- 

 wives do not know of their 

 existence, while even those 

 of the more intelligent class 

 often fail to appreciate their 

 close relation to household 

 economy. Few housewives, 

 it is safe to say, have 

 ever seen them or been aware of their existence. Never- 

 theless they are so constantly at work upon all kinds of 

 food products in the pantry, that the affairs of the house- 

 hold are in a state of more or less constant warfare against 

 these invisible, unrecognized, and unknown foes. They 

 are more serious enemies than molds or yeasts. Chiefly 

 to their presence and activity is due the fact that the 

 preservation of foods, even for a few days, is frequently 



J18 



Fig. 46. Showing the comparative size 

 of molds (a), yeast (i and c), and bac- 

 teria (d). 



