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relation between these and the others ? 1 imagine not. How 
can air or water become light ? or light be liquefied ? Unless 
all natural forces be correlated, general deductions from the 
correlation of a portion of them must fail. Correlation of part 
of the natural forces cannot govern the whole, nor can it 
therefore lead to any definite conclusion in our study of natural 
phenomena. 
If it be intended to connect the doctrine of correlation of 
forces in any way with vitality, I conceive it must be unsuc- 
cessful. Mr. Grove quotes Dr. Carpenter as suggesting “ the 
probability of extraneous forces, as heat, light, and chemical 
affinity, continuously operating upon the material germ, so 
that all that is required in this is a structure capable of 
receiving, directing, and convertiug these forces into those 
which tend to the assimilation of extraneous matter, and the 
definite development of the particular structure.” The material 
germ remains to be discovered. If it were under our hand, 
it might receive extraneous affections, as water receives heat ; 
but directing is a property of life — perhaps even confined to 
its highest forms. The water does not direct the heat in the 
production of steam. The external force may direct the 
material structure, but the directing is as unpremeditated as 
the impelling physical movement is involuntary. Instead of 
this, the very material structure itself is called upon to direct 
those forces to an invariable and given end, converting them 
into other forces tending to .form a totally different structure 
— meaning, of course, living structure. Is this so ? Mr. 
Grove inclines to the affirmative, and supports his views thus : 
“ As by the artificial structure of a voltaic battery, chemical 
actions may be made to co-operate in a definite direction, so 
by the organism of a vegetable or animal, the mode of motion 
which constitutes heat, light, &c., may, without extravagance, 
be conceived to be appropriated and changed into the forces 
which induce the absorption and assimilation of nutriment, 
and into nervous agency and muscular power.” 
Now, I think this may not be received without the greatest 
extravagance. There can be no doubt about the actions of a 
voltaic battery. But in all such reasonings it appears to be 
forgotten that life is there the directing power, not the insen- 
sate machine, nor the force with which it is connected. It is 
organism working to a specific purpose, not physical forces 
appropriated and changed by the material machine or directed 
by it. Life charges the battery, and guides the results. 
Vital power is the operator throughout, by means of its 
exponents, the brain and the muscle of the operator. It is 
vitality compelling the elements ; not the elements engaged in 
