ITS METHODS AND’ TENDENCIES. 467 
designate as material. The beautiful and important dis- 
coveries which have followed researches into the correla- 
tion and conservation of forces by pointing to a unity of 
all the forces in the material world have naturally prompt- 
ed efforts to centralize, with electricity, magnetism, and 
chemical affinity, that which we know as vital force. But 
a moment’s reflection will show us how far removed is this 
vital force from all others with which it has been com- 
- pared. 
The nicest manipulations of chemical science will prob- 
ably fail to detect a difference in composition between the 
microscopic germs of two cryptogamous plants. Each 
consists of the same elements, carbon, nitrogen, hydrogen, 
and oxygen, in nearly or quite the same proportions. 
Both may be planted in a soil which laborious mixture 
has rendered homogeneous, and subsequently supplied 
with the same pabulum, and yet, in virtue of some inseru- 
table, inherent principle, one develops a humble moss, 
and the other rises into the beauty, symmetry, and even 
grandeur of a tree fern. The same may be said of the 
Spermatozoa of the mouse and the elephant. Indeed all 
the phenomena which attend the reproduction of species 
are totally at variance and incompatible with those which 
mark the action of material laws. Why, in physical cir- 
cumstances differing toto cælo, does the germ produce a 
plant or animal so closely copying the parent? and whence 
this tenacity of purpose in the germ which reproduces, 
through a long line of posterity, the trivial characteristics 
of a remote ancestor. Even within our limited observa- 
tion we have been struck by the reappearance in the 
grandchild of the voice, the gesture, the stature, the fea- 
tures, or some other marked peculiarity of his grandsire. 
Whence comes the force of the axiom that “blood will 
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