322 STRUCTURE AND LIFE HISTORIES 
things plants or animals. Not being able to manu- 
facture their own food, they must find it ready made. 
SAPROPHYTISM 
302. Decay. Perhaps the simplest case of the nutrition 
of non-green plants is the absorption of food from the 
organic remains of other plants or of animals. When 
the spores or other reproductive bodies of such plants 
begin to grow upon such a substratum, they secrete 
various enzymes which begin to disintegrate it, reducing 
it to simpler, soluble substances. This is the process 
commonly known as "decay," and the plants which 
cause it are called saprophytes. 1 The word "decay" 
is derived from a Latin word, decidere, which means 
to fall apart, in allusion to the fact that the decaying 
substance is being disintegrated or broken down into 
simpler substances, which are recombined by assim- 
ilation, in the cells of the saprophyte, into protoplasm 
like its own. Such a state of existence is called sapro- 
phytism. 
303. Fungus -saprophytes. Among the more familiar 
saprophytic plants may be mentioned the common bread- 
mold, the fungi that are instrumental in ripening cheese, 
the so-called "mildews," which often grow on old moist 
pieces of leather, and numerous other filamentous fungi; 
the bacteria which cause the decay of meat and other 
substances, bacteria which cause the retting of flax stems, 
thus freeing the bast fibers from which linen is made by 
causing the decay or rotting away of the remainder of 
the tissue, the bacteria which convert cabbage leaves 
1 From the Greek words sapros, rotten + phyton, plant. 
