PROCESSES OF LIFE REVEALED BY THE MICROSCOPE. 383 



unfavorable. It was the last of the forms of energy to appear upon 

 this planet and it will be the first to disappear. 



In brief, it seems to me that the present state of physical and physi- 

 ological knowledge warrants the assumption, the working hypothesis, 

 that life is a form of energy different from those considered in the 

 domain of physics and chemistry. This form of energy is the last to 

 appear, last because more conditions were necessary for its manifesta- 

 tions. It, like the other forms of energy, requires a material vehicle 

 through which to act, but the results produced by it are vastly more 

 complex. Like the other energies of nature, it does not act alone. It 

 acts with the energies of the physicist, but as the master; and under 

 its influence the manifestations pass infinitely beyond the point where 

 for the ordinary energies of nature it is written "thus far and no 

 farther." 



It can be stated without fear of refutation that every physiological 

 investigation shows with accumulating emphasis that the manifesta- 

 tions of living matter are not explicable with only the forces of dead 

 matter, and the more profound the knowledge of the investigator the 

 more certain is the testimony that the life energy is not a mere name. 

 And, strange to say, the physicist and the chemist are most emphatic 

 in declaring that life is an energy outside their domain. 



The statements of a chemist, a physicist, and a biologist are added. 

 From the character and attainments of these men, their testimony, given 

 after years of the most earnest investigation and reflection, is worthy 

 of consideration: 



When a celebrated chemist was asked if he believed that a leaf or a 

 flower could be formed or could grow by chemical forces, he answered: 



I would more readily believe that a book on chemistry or on botany 

 could grow out of dead matter by chemical processes. — Liebig. 



The influence of animal or vegetable life on matter is infinitely beyond 

 the range of any scientific inquiry hitherto entered on. Its power of 

 directing the motions of moving particles, in the demonstrated daily 

 miracle of our human free will, and in the growth of generation after 

 generation of plants from a single seed, are infinitely different from any 

 possible result of the fortuitous concourse of atoms; and the fortuitous 

 concourse of atoms is the sole foundation in philosophy on which can 

 be founded the doctrine that it is impossible to derive mechanical effect 

 from heat otherwise than by taking heat from a body at a higher tem- 

 perature, converting at most a definite proportion of it into mechanical 

 effect, and giving out the whole residue to matter at a lower tempera- 

 ture. — Sir William Thomson (Lord Kelvin). 



The anagenetic [vital] energy transforms the face of nature by its 

 power of assimilating and recompounding inorganic matter, and by its 

 capacity for multiplying its individuals. In spite of the mechanical 

 destructibility of its physical basis (protoplasm) and the ease with 

 which its mechanisms are destroyed, it successfully resists, controls, 

 and remodels the catagenetic [physical and chemical] energies for its 

 purpose. — Ooi>e. 



