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laws, this body would so far not be material. This is not at 
all in question, and so far as a correct conception of an animal 
body is concerned, it is superfluous to argue the point. What 
is in question is whether this body is capable of no other 
functions than these, not whether it is a machine or a voltaic 
battery, but whether it is not something more. The question 
is not whether so far as it is material it is subject to material 
laws, but whether it is not also a living body, and what forces, 
relations, and laws this conception implies.* 
What is most surprising is, not that a certain class of scien- 
tific men do not see this distinction, but that so many insist in 
one breath that no scientific theory can be accepted which is 
incapable of mathematical formulization and experimental veri- 
fication, and in the next breath adopt a theory of life on a me- 
chanical and chemical basis, the laws of which they do not 
profess to have formulated in numbers, nor to have tested the 
alleged facts by experiment. Prof. Tyndall insists that “ the 
interdependence of our day has become quantitative — expres- 
sible by numbers ” — and that where law cannot be formulated 
by numbers there is no science. W e insist that if under this 
definition, Psychology, Morals, and Theology are excluded 
from the domain of science, Physiology should be excluded 
also, and yet the whole doctrine of development, — with heredity 
and its variations and integrations, and all the nomenclature 
by which the soul is demonstrated to be but a higher potency 
of matter, and personality to be an ideal fiction, and God an 
entirely superfluous hypothesis — is derived from the very 
operations of life, scarcely a single one of which if tried by 
the criterion in question has been scientifically fixed or for- 
mulated. f 
* Since writing the above, we happened to open the often-read discourse 
of Du Bois Reymond, of Aug. 14, 1872, on the limits of the hiowlcthje of 
nature. On page 26, speaking of a supposed ideal knowledge of the physiolo- 
gical processes, analogous to our actual knowledge of astronomical movements 
and laws, he says : — In that case, “ muscular contraction ; glandular secre- 
tion ; electrical pulsation ; optical illumination ; ciliary movement ; the 
growth and chemism of plant-cells ; the impregnation and development of the 
egg ; all these note hopelessly dark processes would then be as transparent as 
the movements of the planets.” It would seem that these processes are no 
longer dark to Prof. Tyndall’s illuminated vision. 
t Pi'of. Tyndall asserts, not infrequently, with unqualified positiveness, 
that sciences cease where mechanical relations cannot be mathematically 
determined. He objects to any scientific recognition of the phenomena of 
spirit, in such language as this : — “ If we are true to these canons we must 
deny to subjective phenomena all influence on physical processes. Observa- 
tion proves that they interact, but in passing from the one to the other we 
meet a blank, which mechanical deduction cannot fill.” He seems to over- 
