CHEMIC X AL CHANGES. 



of phenomena, whose true connection with 

 others, whose ultimate cause is still un- 

 known. 



If we assume that al 1 the phenomena ex- 

 hibited by the organism of plants and ani- 

 mals are to be ascribed to a peculiar cause, 

 different in its manifestations from all other 

 causes which produce motion or change of 

 condition ; if, therefore, we regard the vital 

 force as an independent force, then, in the 

 phenomena of organic life, as in all other 

 phenomena ascribed to the action of forces, 

 we have the statics, that is, the state of equi- 

 librium determined by a resistance, and the 

 dynamics, of the vital force. 



All the parts of the animal body are pro- 

 duced from a peculiar fluid, circulating in 

 its organism, by virtue of an influence resid- 

 ing in every cell, in every organ, or part of 

 an organ. Physiology teaches that all parts 

 of the body were originally blood ; or that 

 at least they were brought to the growing 

 organs by means of this fluid. 



The most ordinary experience farther 

 shows, that at each moment of life, in the 

 animal organism, a xamimifid,. Change of 

 matter, more or less accelerated, is going 

 on ; that a part of the structure is transformed 

 into unorganized matter, loses its condition 

 of life, and must be again renewed. Physi- 

 ology has sufficiently decisive grounds for 

 the opinion, that every motion, every mani- 

 festation of force, is the result of a transfor- 

 mation of the structure or of its substance; 

 that every conception, every mental affec- 

 tion, is followed by changes in the chemical 

 nature of the secreted fluids; that every 

 thought, every sensation, is accompanied by 

 a change in the composition of the sub- 

 stance of the brain. 



In order to keep up the phenomena of life 

 in animals, certain matters are required 

 parts of organisms, which we call nourish- 

 ment. In consequence of a series of altera- 

 tions, they serve either for the increase o 

 the mass (nutrition ,) or for the supply o 

 the matter consumed (reproduction,) or 

 finally, for the production of force. 



II. If the first condition of animal life b< 

 the assimilation of what is commonly callec 

 lourishment, the second is a continual 

 absorption of oxygen from the atmos- 

 phere. 



Viewed as an object of scientific research, 

 animal life exhibits itself in a series of 

 phenomena, the connection and recurrence 

 of which are determined by the changes 

 which the food and the oxygen absorbed 

 from the atmosphere undergo in the organ- 

 ism under the influence of the vital force. 

 kAll vital activity arises from the mutual 

 lion of the oxygen of the atmosphere and 

 e elements of the food. 

 In the processes of nutrition and repro- 

 duction, we perceive the passage of matter 

 from the state of motion to that of rest 

 (static equilibrium ;) under the influence of 

 die nervous system, this matter enters again 

 into a ,tate of motion. The ultimate causes 



f these different conditions or tne vital force 

 are chemical forces. 



The cause of the state of rest is a resist- 

 ance, determined by a force of attraction 

 (combination,) which acts between the 

 smallest particles of matter, and is mani- 

 'ested only when these are in actual contact, 

 or at infinitely small distances. 



To this peculiar kind of attraction we 

 may of course apply different names ; but 

 the chemist calls it affinity. 



The cause of the state of motion is to be 

 found in a series of changes which the food 

 undergoes in the organism, and these are 

 the results of processes of decomposition, to 

 which either the food itself, or the structures 

 formed from it, or parts of organs, are sub- 

 jected. 



The distinguishing character of vegetable 

 life is a continued passage of matter fromj 

 the state of motion to that of static equili J 

 brium. While a plant lives, we cannot 

 perceive any cessation in its growth ; no 

 part of an organ in the plant diminishes in 

 size. If decomposition occur, it is the re- 

 sult of assimilation. A plant produces 

 within itself no cause of motion ; no part 

 of its structure, from any influence residing 

 in its organism, loses its .state of vitality, 

 and is converted into unorganized, amor- 

 phous compounds ; in a word, no waste 

 occurs in vegetables. Waste, in the animal 

 body, is a change in the state or in the 

 composition of some of its parts, and conse- 

 quently is the result of chemical actions. 



The influence of poisons and of remedial 

 agents on the living animal body evidently 

 shows that the chemical decompositions and 

 combinations in the body, which manifest 

 themselves in the phenomena of vitality, 

 may be increased in intensity by chemical 

 forces of analogous character, and retarded 

 or put an end to by those of opposite cha- 

 racter ; and that we are enabled to exercise 

 an influence on every part of an organ by 

 means of substances possessing a well- 

 defined chemical action. 



As, in the closed galvanic circuit, in con- 

 sequence of certain changes which an inor- 

 ganic body, a metal, undergoes when placed 

 in contact with an acid, a certain something 

 becomes cognizable by our senses, which 

 we call a current of electricity ; so, in the 

 animal body, in consequence of transforma- 

 tions and changes undergone by matter 

 previously constituting a part of the organ- 

 ism, certain phenomena of motion and 

 activity are perceived, and these we call 

 life, or vitality. 



The electrical current manifests Itself in 

 certain phenomena of attraction and repul- 

 sion, which it excites in other bodies na- 

 turally motionless, and by the phenomena 

 of the formation and decomposition of che- 

 mical compounds, which occur every where, 

 when the resistance is not sufficient to arrest 

 the current. 



It is from this point of view, and from no 

 other, that chemistrv ought to contemplate 

 'B 



