174 ZOOCHEMICAL PROCESSES. 



become deposited ; in this manner, for instance, fat and horn-cells 

 are produced in the animal organism, and gum, resins, and oils 

 in vegetable bodies. 



If we consider life in the organic substrata from this point of 

 view as an incessant movement of molecules and molecular aggre- 

 gations, as an uninterrupted process in which beginning, progress, 

 and termination of motions intersect one another at the same 

 time, it will no longer excite our surprise that the chemist has 

 hitherto been unable to trace physiologico-chemical processes in 

 their various directions, to detect from amid a seeming chaos all 

 the substrata which concur in effecting such a process, and to 

 determine with exactness their different properties. Nor must the 

 chemist flatter himself that he can at once, in the midst of the 

 perpetual metamorphosis of matter, arrest the life and motion of 

 the organic substrata, and thus examine the position of the 

 chemical molecules at the moment of rest; and he would be equally 

 in error were he to assume that the substances he has separated 

 are entirely the same as they were when all the molecules in the 

 organised body were in a state of vital motion. It is impossible 

 to arrest at will the machinery of molecular motion, to bring the 

 moved parts at once to rest and render them rigid, to make them 

 maintain the same unstable equilibrium, or to separate the indi- 

 vidual parts of this chemico-vital mechanism. As we are not able 

 to analyse ferments because it is by the very act of self-metamor- 

 phosis that they generate fermentation, so also does it defy the 

 efforts of the chemist to investigate organised matter itself ; for his 

 solvents and reagents affect only the products of molecular motion 

 in the living body, but not the act of motion itself. If the scalpel 

 of the anatomist, which only reveals to us the often-mangled 

 structures of life, has yielded such grand and brilliant results 

 regarding material life as to form the basis of physiology, what 

 may we not look forward to from the attainment of a more pro- 

 found insight into the molecular movements ? or need we wholly 

 despair of being able, by physical investigations, to discover some 

 magnitudes which will enable us to calculate the highest unknown 

 magnitude ? 



Many persons have found it very difficult to understand how 

 inorganic matter derived from the external world, can become 

 subject to organic laws within the sphere of the living organism, 

 and undergo the metamorphoses appertaining to that sphere with- 

 out the co-operation of dynamical laws belonging exclusively to 

 life. It was thought that the magic circle of the vital principle 

 was sufficiently restricted if the mineral substances which we meet 



