2 APPENDIX. 



qualities on organized matter-similar to those imputed to a vital principle, and different 

 from those which characterize Unorganized matter, although they cannot point out the 

 difference otherwise than by calling them vital, they virtually admit the existence of the 

 principle against which they contend ; for what principle in nature, we would ask, can 

 be shown to exist, or how can its existence be rationally inferred, but by certain pro- 

 perties and qualities, which are peculiar to itself, and which, moreover, as respects this 

 principle, are dissimilar and greatly superior to, and indeed hold a controlling influ- 

 ence over all the other properties of matter with which we are acquainted ? 



Such therefore being the case, we are justified in recurring to the belief in a vital 

 principle which, allied to matter, controls its changes and forms, and to which princi- 

 ple the laws and affinities of matter entirely subject whenever they are embraced within 

 its sphere of action. By means of this superior principle, we are enabled to explain 

 the phenomena of the organized preation and of the human economy, but without re- 

 ference to it we are lost in the mazes of vague hypothesis and groundless supposition. 



It has been objected to the existence of this principle, that we cannot demonstrate it 

 to the senses in any form unconnected with matter. But we are not contending for the 

 existence of a principle which is material, according to the received notions respecting 

 matter, otherwise there would be at once an end of the argument ; it is, therefore, no 

 evidence of the non-existence of this principle, that it does not become visible to our 

 senses, in an uncombined form : it is, however, sufficiently demonstrable by its effects, 

 in alliance with matter, in which state it presents proofs of its being equal to those from 

 which we infer the existence of matter itself. 



From these and many other considerations that may be adduced, we conclude that 

 life is a first principle in nature ; that it exists in various degrees of energy, and in di- 

 versified conditions and forms throughout her domains ; and that these diversified states 

 of vital existence are continued, as far as the operation of extraneous causes will admit, 

 by a specific process, which gives rise to the production of similar beings by means of 

 ova and germs. 



It will be perceived that the generation by which vegetable and animal bodies are 

 perpetuated, involve the belief that the ova or germs convey an emanation from the pa- 

 rent of a specific portion of vitality. 



As, however, we can form no just conceptions of such a principle but by its effects, 

 and as we have no experience of these effects unconnected with matter, so we are war- 

 ranted in the conclusion, that the vital influence is associated with the molecules of 

 matter forming the impregnating secretions, and the sensible bulk of the ovum. This 

 is its lowest state of activity or energy, and its influence is chiefly manifested, under 

 such circumstances, in preserving the elements of matter with which it is associated 

 from entering into the combinations to which the chemical affinities of these elements 

 dispose them. 



The hibernation of animals presents this principle also in its lower degree of activity. 

 In either case, and indeed under every circumstance, it is a.cted upon and excited to an 

 exalted state of existence by most of the active agents in nature. The electric fluid, 

 heat, and other powers have this effect, while some appear to produce a contrary im- 

 pression. 



The manner in which several of the active agents of inorganic nature thus influence 

 the energy of the vital principle appears, to have been the chief reason why these 

 powers hare been substituted for vitality itself. 



We have stated, that the manifestations of this principle throughout the vegetable 

 and animal kingdoms present considerable difference in degree. Its character in the 

 vegetable creation is more uniform, and its phenomena more simple. We perceive in 

 this kingdom, under circumstances which furnish the usual stimuli, that the vital ope- 

 rations of digestion, circulation, respiration, and assimilation, go forward. As soon, 

 however, as the exciting causes are withdrawn, this principle subsides to a state of less 

 activity ; and the integrity of such organs and textures as are necessary to the growth 

 and propagation of the species, is merely preserved by its influence until a returning 

 impulse excites its energies. 



As we advance in the scale of the animal creation, the operations of this principle be- 

 come more distinct and numerous, and the mechanism provided for the performance 

 of them more manifest and complex. As they are performed in man and in the more 

 perfect animals, may be gathered from the body of the work and the notes which 

 follow. 



