PLANTS THAT ARE ATHLETES 73 
the game, they lose life. And each act of theirs is 
to benefit not only themselves but also their chil- 
dren. In this they are like human parents, who, 
in order to benefit their children, frequently make 
great sacrifices, 2nd often even risk their own lives; 
in the same way plants take many risks to better 
the condition of their offspring. 
There are a large number of plants which pos- 
sess the power of spontaneous motion, very similar 
to that displayed by the lower forms of animals. 
A striking example of this is found in one of 
the Alge, which has an undulating motion pre- 
cisely like that of certain lower animals. In some 
forms of fresh-water Algae, reproduction takes 
place by the formation of “zoospores” which, though 
exceedingly small, are covered partly or entirely 
with tiny cilia or hairs. After these small zoo- 
spores free themselves from the parent plant, the 
cilia begin to move very rapidly. In addition to 
this vibrating of the cilia, the body of the zoospore 
itself has a rotating movement on its axis, caused by 
spontaneous contractions; and as a result of these 
civilised actions the entire plant passes through the 
water with a motion very similar to that of a fish 
swimming. This continues for a period of from 
one to three hours, as if, in a boy-like water-frolic, 
the youthful plant were making the most of its 
