3?6 FRA GMENTS 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 



