218 APPENDIX. [No. XIII. 



Nor is man's power limited to the application of these forces upon 

 inorganic matter alone, but he can use them also to influence vegetation. 

 Regard these little wild crabs, and see how cultivation has converted the 

 same fruit into this large apple. Look also at these common hedge-nuts, 

 changed by cultivation into the delicious filbert. I need hardly say that 

 this power is only possessed by man. 



Animals are as much under the power of man as plants are ; he can 

 improve their breed, and reduce them to subjection. The common use of 

 horses is an example of that nature. One animal, however, cannot employ 

 another animal. Who, for instance, ever saw an elephant drawn by camel- 

 leopards P (Applause.) And yet, we might readily forget that the sub- 

 jection of animals belongs to man alone. 



We have now shown that man can employ heat, light, attraction, 

 electricity, sound, the vegetable and animal bodies. Now, what is the 

 nature of these powers which he uses P Attraction is an abstraction of 

 a material property ; heat is the same ; so is electricity, sound, force, &c. 

 The powers of animals and vegetables are in like manner the results of 

 matter. We may, therefore, class all these powers together by stating, 

 that man can employ matter to act upon other matter; man is not confined 

 to the use of any particular piece of matter to produce these results, but 

 any piece of matter will equally suit his purpose. We therefore find that 

 man takes a higher stand, for he employs abstractions arising from the 

 properties of matter. 



To recapitulate the leading phenomena exhibited by man, we find that 

 he is composed of integral matter, held together by internal forces ; that 

 the matter is in two physical states, solid and fluid ; that actions are con- 

 tinually taking place by reason of external forces ; that he acts not only 

 upon immediate but upon bygone or antecedent impressions. In all these 

 conditions, however, he is similar to animals ; but the human being has 

 the power of acting upon an arrangement and combination of simple 

 material impressions, or, in other words, he acts upon their abstractions. 

 To separate man from all other material bodies, we may define him to be a 

 being acting upon the abstractions of material impressions. 



In all human operations, matter must be employed, but man can only 

 use the properties with which matter is endowed; he can neither add a 

 new property, nor subtract an old one. Man's power, then, is confined to 

 the use of the properties of matter ; but though he cannot control matter, 

 he perceives there must be a Supreme Power which in the first instance 

 caused matter to have properties, and who, by the exertion of the same 

 power, may will these properties to cease, or new ones to supervene. The 

 contemplation of the Great Controller of the powers of matter forms the 

 limit of the investigations of medical science, for at that point medical 

 science ends and natural theology begins. 



We are now in a condition to determine the means which are in our 

 hands to act upon the human body. We can act upon it directly, by 

 matter, through its power of attraction. We can act upon it also by heat, 

 light, electricity, force, sound, as in the case of animal, vegetable, or 

 mineral bodies. We have, however, another power by which we can act 

 upon man — we may act upon his mind by abstractions. The influences of 

 mental impressions may be inferred from deaths occui-ring from joy, fear, 

 or other strong emotions. Let me, however, warn you and entreat you 



