CHAPTER III 



CONDITIONS FAVORING MOLD GROWTH 



Moisture. The factor of primary importance is water. 

 A vigorous growth of molds needs an abundance of mois- 

 ture, and in dry material they will not grow at all. This 

 moisture may be supplied by the air in which the food is 

 kept, or by the food itself. 



1. Many materials which do not contain in themselves 

 enough water to support the development of molds will 

 serve as a fine locality for mold growth, provided they are 

 kept in a sufficiently damp atmosphere. If the air of a 

 room becomes damp or " close," as we say, it is almost 

 certain that molds will begin to grow upon any organic 

 substance. Thus a large variety of materials in the house- 

 hold, ordinarily free from molding, may show signs of 

 mildew during a damp season. The mustiness of a closed 

 room is due to the presence of molds and is always an 

 indication of dampness, for dry rooms neither show signs 

 of mold nor do they smell musty. 



2. Some materials contain within themselves sufficient 

 water to produce a vigorous development of molds quite 

 independent of the moisture present in the air. Fruits, 

 for example, are so full of water that it makes little differ- 

 ence to them whether the atmosphere in which they are 

 kept is dry or saturated with moisture. If the mold once 

 gets a start, the fruit itself furnishes all necessary water. 



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