MOLDS. 



35 



grow the spores which are to reproduce the species. 

 Figs. 19 and 20. Each head produces thousands of 

 dust-like spores. Fig. 21. This is the 

 common method of reproduction in the 

 molds, although some, like the bacteria be- 

 low them in the scale of nature, break the 

 parent cell into segments, while others send 

 off buds like yeast. These buds form di- 

 rectly the second generation. 



When the invisible spore falls upon a 

 moist, warm surface, it immediately begins 

 to grow by sending out the mycelium 

 branches, which will then proceed as before 

 to develop more spore-bearing cells. 



Sometimes these mycelium cells pene- 

 trate into the food substance, very much 



r IG. 20. 



like the roots of the higher plants. 



One of the effects of mold growth is seen in the soft- 

 ening of cellulose in fruits, vegetables, etc. This makes 

 their decomposition by the bacteria more speedy and 

 thorough. Out-of-doors this action is of great use in 

 the economy of Nature, but inside our houses the pres- 

 ence and growth of molds should be guarded against 

 in every way. 



In general, molds will grow with less moisture than 

 bacteria, and -some of them flourish in the light. They 

 increase rapidly after rainstorms and are much less 

 affected than the bacteria by winds. They need or- 

 ganized food, as we well know from the places where 

 we find them growing bread, meat, leather, sugary 

 liquids, or even in vinegar. 



Hold 



Spores 



