35 
MOLDS. 
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 
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. 
Mold 
Spores 
