180 THE HUMAN SIDE OF PLANTS 
On the other hand, there are numerous tiny ani- 
mals found in ponds, lakes, and rivers, and near 
rocky cliffs in the oceans, whose very bodies simu- 
late in every respect the most delicately tinted 
flowers, or even a handful of jewels; yet, with all 
these apparently inconsistent qualities, these won- 
derful, flower-like beings belong unquestionably 
to the animal kingdom. 
It is practically impossible to make a distinction 
between the two kingdoms. There are no hard 
and fast lines in nature. In defining the limits be- 
tween these two kingdoms, scientists in dealing with 
the lower forms of life have made many errors; 
and as a result a number of the lower forms of both 
animal and vegetable life have, at different periods 
of their existence, been classed as both plants and 
animals. 
Even at this advanced age animals, such as the 
Sertularia, are gathered and preserved as sea- 
mosses! Of course, this is done only by people who 
are unaware that these leaf-like animals are really 
not plants. 
In 1850 all bacteria were assigned to the vege- 
table kingdom, but now they are fully recognised 
as members of the animal kingdom. Of course 
one knows that a lily is a plant, and that a squirrel 
is an animal; but in the lower forms of life it is 
