3?6 FRAGMENTS OF SCIENCE. 
make such free use of the terms insolence, outrage, pro- 
fanity, and blasphemy. They obviously lack the sobriety 
of mind necessary to give accuracy to their statements, or 
to render their charges worthy of serious refutation. 
CHAPTER XXVI. 
VITALITY. 
THE ORIGIN", growth, and energies of living things are 
subjects which have always engaged the attention of think- 
ing men. To account for them it was usual to assume a 
special agent, free to a great extent from the limitations 
observed among the powers of inorganic nature. This 
agent was called vital force; and, under its influence, plants 
and animals were supposed to collect their materials and 
to assume determinate forms. Within the last few years, 
however, our ideas of vital processes have undergone pro- 
found modifications; and the interest, and even dis- 
quietude, which the change has excited are amply evidenced 
by the discussions and protests which are now common, re- 
garding the phenomena of vitality. In tracing these 
phenomena through all their modifications, the most 
advanced philosophers of the present day declare that they 
ultimately arrive at a single source of power, from which 
all vital energy is derived; and the disquieting circumstance 
is that this source is not the direct fiat of a supernatural 
agent, but a reservoir of what, if we do not accept the 
creed of Zoroaster, must be regarded as inorganic force. 
In short, it is considered as proved that all the energy 
which we derive from plants and animals is drawn from 
the sun. 
A few years ago, when the sun was affirmed to be the 
source of life, nine out of ten of those who are alarmed by 
the form which this assertion has latterly assumed would 
have assented, in a general way, to its correctness. Their 
assent, however, was more poetic than scientific, and they 
were by no means prepared to see a rigid mechanical 
signification attached to their words. This, however, is 
the peculiarity of modern conclusions that there is no 
creative energy whatever in the vegetable or animal organ- 
ism, but that all the power which we obtain from the 
