48 
HOUSEHOLD BACTERIOLOGY 
Bacteria as 
Scavengers 
As soon as an organism begins to live it begins to 
die; that is, certain cells or parts of cells die and are 
perhaps cast off from the rest that the whole may 
not be injured. Animals and 
plants die and become dan¬ 
gerous to the welfare of 
other animal life, especial¬ 
ly to man. The wastes of 
life, of his own life even, are 
man’s greatest menace. 
Here come to his aid these microscopic scavengers, 
the bacteria. No doubt the molds assist in the process 
but the balance of the work is done by the bacteria pres¬ 
ent in such infinite numbers everywhere on the earth 
where organic matter exists. 
Through their agency all 
dead animal and vegetable 
substances—that is, all or¬ 
ganic matter—are changed in¬ 
to inorganic matter, into the 
chemical compounds or ele¬ 
ments out of which they were 
originally constructed, and 
which are harmless or helpful 
to the life of the world. 
A tree falls in the woods; an elephant or a bird 
dies in the jungle; just then and there the millions of 
bacteria in the soil and the air are ready to seize upon 
the dead bodies, and in time all the animal and vege- 
Fig. 29. Bacteria Found in 
Soil and on the Roots of 
Clover, Peas and Other 
Leguminous Plants. 
Fig. 28. Bacteria in Soil 
which Help in Making 
Plant Food. 
