Scientific Lectures. 239 



So, wlien the oxygen and the zhic of the ore are separated in the 

 fnrnace, tlie actual energy of heat becomes the potential energy of 

 clieniical attraction, which again becomes actual in the form of elec- 

 tricity when tlie zinc isdissolved in an acid. We see, then, that not 

 only may any form of force or actual enei'gy be stored up as any form 

 of attraction or potential energy, but that the hitter, from wliatsoever 

 source deriv^ed, may appear as heat, light, electricity, or mechanical 

 motion. 



Having now established the fact of correlation for tlie physical 

 forces, we have next to inquire what are the evidences of the correla- 

 tion of the vital forces with tliem. But in the first place it must be 

 remarked that life is not a simple term like heat or electricity ; it 

 is a complex term, and includes all those phenomena which a living 

 body exhibits. In this discussion, therefore, we shall use the term 

 vital force to express only the actual energy of the body, however 

 manifested. As to the attractions or the potential agency of the organ- 

 ism, nothing is more fully settled in science than the fact that these 

 are precisely the same within the body as without it. Every particle 

 of matter within the body obeys implicitly the laws of the chemical 

 and physical attractions. No overpowering or supernatural agency 

 comes in to complicate their action, which is modified only by the 

 action of the others. Vitality, therefore, is the sum of the energies 

 of a living body, both potential and actual. 



Moreover, the important fact must be fully recognized that in liv- 

 ing beings we have to do with no new elementary forms of matter. 

 Precisely the same atoms which build up the inorganic fabric, com- 

 pose the organic. In the early days of chemistry, indeed, it was 

 supposed that the complicated molecules which life produced were 

 beyond the reach of simple chemical law. But as more and more 

 complex molecules have been, one after another, produced, chemistry 

 has become re-assured, and now doubts not her ability to produce 

 them all. A few years hence, and she will doubtless give us quinine 

 and ])rotagon,as she now gives us coumarin and neurine, substances 

 the synthesis of which was but yesterday an impossibility.* 



* Compare Odling, Wm., Lectures on Animal Chemistry, London, 1866. "In broad antagonism 

 to the doctrines which only a few years back were regarded as indisputable, we now find tha„ ths 

 chemist, like the plant, is capable of producing from carbonic acid and water a whole host of organic 

 bodies, and we see no reason to question his ultimate ability to reproduce all animal and vegetable 

 principles whatsoever." (p. 52.) 



"Already hundreds of organic principles have been built up from their constituent elements, and 

 there is now no reason to doubt our capability of producing all organic principles whatsoever in a 

 similar manner." (p. 56.) 



Dr. Odling is the successor of Faraday as Fullerlan Professor of Chemistry in the Royal Institution 

 of Great Britian. 



