20 THE DOCTRINE OF DESCENT. 



a motion, invisible, it is true, but sensible as heat. But 

 likewise the combination of the particle of oxygen intro- 

 duced into the animal body by the respiration, with the 

 un-oxygenated constituents of the blood, is a motion sub- 

 ject to computation, and manifesting itself as oxydation, 

 combustion, or the evolution of animal heat. This chem- 

 ical act of combustion keeps the animal steam-engine 

 in motion. 



In this way, by the application of mechanical princi- 

 ples, modern physiology has traced to their causes a 

 great number of organic processes, and the phantom of 

 vital force, which formerly reigned paramount over the 

 whole intestinal canal, incited the glandular cells and the 

 muscular fibres to their offices, and glided along the 

 nerves, now scarcely knows where to breed disturbance. 



Thus the investigation of nature does not shrink from 

 enrolling life and the processes of life in the world of the 

 comprehensible. We are foiled only at the conception of 

 matter and force. But we are much further advanced 

 than Schopenhauer and his adherents, who for the idea of 

 Force substitute that of Will; for we have analyzed into 

 their several self-conditioned momenta a multitude of 

 processes, which the word " Will," incomprehensible in 

 itself, is supposed to explain in their totality; and much 

 further also than the fashionable philosopher of the day, 

 von Hartman, who regales us with .the agency of the 

 " unknown " in the domain of the organic world. 



" And yet," Dubois-Reymond thus formulates another 

 limit, " a new incomprehensible appears in the shape of 

 consciousness even in its lowest form, the sensation of 

 desire and aversion. It is, once for all, incomprehensible 

 how, to a mass of molecules of nitrogen, oxygen, hydro- 



