20 THE DOCTRINE OF DESCENT. 



is transformed into the atomic motion of the places 

 struck, a motion, invisible, it is true, but sensible as 

 heat. But likewise the combination of the particle of 

 oxygen introduced into the animal body by the respi- 

 ration, with the un-oxygenated constituents of the blood, 

 is a motion subject to computation, and manifesting 

 itself as oxydation, combustion, or the evolution of 

 animal heat. This chemical act of combustion keeps 

 the animal steam-engine in motion. 



In this way, by the application of mechanical prin- 

 ciples, 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, incomprehen- 



