CHAPTER III 

 MICROORGANISMS IN THE HOUSEHOLD 



Thanks to these discoveries it is now well recognized 

 that bacteria, yeasts, and molds together form a group of 

 utmost importance in human welfare. Although far too 

 small to*be seen, their rapid rate of reproduction makes 

 them one of nature's strongest forces either for weal or for 

 woe. Their importance in connection with disease and the 

 practice of medicine was recognized many years ago ; and 

 a httle later their significance in agriculture was understood. 

 Still more recently it has come to be appreciated that their 

 relation to the ordinary household, and hence to the house- 

 wife, is even more intimate than to the physician. We 

 are learning that many of the tasks of the housekeeper, 

 some of which may be more or less unpleasant, have their 

 foundation in bacteriology, and we are beginning to recog- 

 nize that these microorganisms constitute the foundation 

 of the demand for cleanliness so forcibly emphasized in 

 modern times. Thus the vague knowledge of the past is 

 growing into a scientific understanding of the subject. 



In the household microorganisms have an important 

 bearing in three directions : 



1. They are the cause of the decay and spoiling of foods 

 and many other products. 



2. They are sometimes of value in the preparation of 

 foods. 



3. They are the cause of contagious and infectious diseases. 



