THE LOWEST POEMS OF LIFE. 
53 
as popularly as I am able, some of those lowly forms of vege- 
table existence that have so greatly excited your admiration.” 
My young visitor expressed her readiness to give me her 
attention ; and, hi the hope that the reader will do the same, I 
venture to proceed with the account of our conversation. 
“ To begin at the beginning. You are of course aware of the 
difference which exists between a physical and a vital force — 
the power that causes an apple to fall to the ground, as distin- 
guished from that which causes it to grow ; and you doubtless 
know that when we see in an organized fabric a vital energy at 
work, operating irrespective of the physical laws, or even in 
opposition to them, we call that energy ‘ life. ’ 
Thus, for exampile, if a tree were to lose one of its branches 
by the blow of an axe, the physical force that we call attraction 
would cause it to fall heavily to the earth ; but if, through the 
vital properties of the tree, a fresh branch were put forth near 
the stump of the old one, it would in all probability grow in the 
opposite direction to that in which the latter fell : the vital 
power of growth being in this instance superior to the physical 
power of attraction. 
Now, although these forces are apparently distinct in their 
nature, yet they are closely interlinked one with another, and 
every day we find a nearer and nearer relationship, if I may so 
call it, between them.* 
However interesting this subject may be, I cannot dwell 
upon it this evening’, and must now tell you that the force or 
energy termed ‘ life/ is, practically speaking, first called into 
operation in a minute cell, or capsule; and that not only all 
plants, but also the bodies of all animals, are made up of an 
assemblage of such cells, more or less modified in form and 
character. 
I say ‘ practically speaking/ because life may be found in 
bodies that do not even lay claim to the designation of a cell, 
as that Amoeba, for example, which you found to be little 
else than a speck of slime ; and yet it possesses a vital power 
sufficient to enable it to digest its food and grow. 
However, even scientific men are satisfied to regard the 
‘ cell ’ as the lowest form of fife ; and those cells that possess 
animal properties they have grouped together under the title of 
Protozoa, from two Greek words signifying the ‘ first animals/ 
whilst those exhibiting the characteristics of the vegetable king- 
dom they call Protopiiyta, or the ‘first plants/ The little objects 
that you compared to Jupiter’s satellites, which moved so 
* See Carpenter’s “ Address on the Correlation of Physical and Vital 
Forces,” delivered at the Eoyal Institution of Great Britain. 
