emotional poetry, was in every case less
when recitation was oral; this is of course accounted for by the
muscular expression. Chemistry teaches that thought-force, like
muscle-force, comes from the food, and demonstrates that the force
evolved by the brain, like that produced by the muscle, comes not from
the disintegration of its own tissue, but is the converted energy of
burning carbon.[48] "Can we longer doubt," says Barker,[49] "that the
brain too, is a machine for the conversion of energy? Can we longer
refuse to believe that even thought force is in some mysterious way
correlated to the other natural forces? and this even in the face of the
fact that it has never yet been measured.[50] Have we not a right to ask
'why a special force (vital force) should be needed to effect the
transformation of physical forces into those modes of energy which are
active in the manifestation of living beings, while no peculiar force is
deemed necessary to effect the transformation of one mode of physical
force into any other mode of physical force?"

Richard Owen says:[51] "In the endeavor to clearly comprehend and
explain the functions of the combination of forces called 'brain,' the
physiologist is hindered and troubled by the views of the nature of
those cerebral forces which the needs of dogmatic theology have imposed
on mankind. * * * Religion, pure and undefiled, can best answer how far
it is righteous or just to charge a neighbor with being unsound in his
principles who holds the term 'life' to be a sound expressing the sum of
living phenomena, and who maintains these phenomena to be modes of
force into which other forms of force have passed from potential to
active states, and reciprocally, through the agency of the sums or
combinations of forces impressing the mind with the ideas signified by
the terms 'monad,' 'moss,' 'plant,' or 'animal.'"

We have now shown that the very forces which give vent to the attributes
of man, are correlated to the physical forces. Let us now consider his
attributes as manifested by his mental powers. There is no doubt the
difference between the mental faculties of the ape and that of the
lowest savage, who cannot express any number higher than four and who
uses hardly any abstract terms for common objects or for the
affections,[52] is still very great and would still be great, says
Darwin, "even if one of the higher apes had been improved or civilized
as much as a dog has been in comparison