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verse. They are also to be considered a* regular ami occasional. 

 Lastly, their mutual or conjoint agencies are to be considered ac- 

 cording to the following order. 



1. MECHANICAL RELATION: 



1st, As mechanical phenomena in food are directly produced by 

 the mechanical agency of the stomach. 



2nd, As mechanical changes in food are produced by relations 

 of the chymical agents furnished by the stomach, with those of the 

 same kind in food, with which the mechanical are in alliance. 



3rd, As mechanical phenomena in food are produced directly by 

 the agency of vital properties of the stomach, or as mechanical 

 phenomena in food are produced by vital properties of the stomach 

 through the medium of the chymicals and their relation with the 

 mechanicals. It is also a matter to be decided, whether this latter 

 (the mediate agency) is not invariable, or in other words whether 

 the direct ever takes place. 



2. CHYMICAL RELATION. 



1st, As chymical changes in food are produced by the chymical 

 matters supplied by the stomach. The changes attributable to this 

 agency are to be specified. 



2nd, As chymical changes in food (if any) are produced by 

 mechanical action of the stomach (this action may perhaps contri- 

 bute towards the process of digestion in birds, by a mechanical 

 mixture of the chymicals of the stomach with those of the food). 

 But the effect of such a relation, if any take place in the human 

 stomach, can be scarcely worth inquiring after. 



3rd, As chymical changes in food are produced by a relation 

 ubsisting between its constituents and the vital properties of the 

 stomach, these changes are to be inquired after and specified. 



3. SPIRITUAL RELATION. 



6. To propose an investigation of the precise relations between 

 vital properties, pre-suppose at least that these properties are known. 

 The investigation would require that the varieties of vital properties 

 contained in food, as well as those belonging to the stomach, should 

 be specified. The question, whether the effects result from priva- 

 tion or addition of properties, in agreement with our doctrines of 

 causation, will require in every topic of these relations to be deter- 

 mined. The relations between individual properties on either side 

 can be known only by distinct experimental combinations: and the 

 integral relation of the spiritual properties belonging to the stomach 

 and those of food, can be known only by a separation of these pro- 

 perties from their alliances, and by rendering them objects of the 

 senses, which we may venture to say will not be done until a method 

 shall be discovered for performing impossibilities. Thus much, 

 however, by way of indicating those points, the possession of which 

 would leave us as well instructed respecting one great operation of the 

 animal economy, as we are of the relation which the parts bear with 

 ach other in the simplest piece of machinery. We must be con* 

 tent for the present with a looser method, which aspires only to 



