NATURAL THEOLOGY. 89 



and certain ; that it is not the less so, because it 

 often begins or terminates with something which 

 is not mechanical ; that whenever it is intelhgible 

 and certain it demonstrates intention and contri- 

 vance, as well in the works of nature, as in those 

 of art ; and that it is the best demonstration which 

 either can afford. 



But whilst I contend for these propositions, I 

 do not exclude myself from asserting, that there 

 may be, and that there are, other cases in which, 

 although we cannot exhibit mechanism, or prove 

 indeed that mechanism is employed, we want not 

 sufficient evidence to conduct us to the same con- 

 clusion. 



There is what may be called the chemical part 

 of our frame ; of which, by reason of the imper- 

 fection of our chemistry, we can attain to no dis- 

 tinct knowledge ; I mean, not to a knowledge, 

 either in degree or kind, similar to that which we 

 possess of the mechanical part of our frame. It 

 does not, therefore, afford the same species of ar- 

 gument as that which mechanism affords ; and yet 

 it may afford an argument in a Iiigh degree satis- 

 factory. The gastric juice, or the liquor which 

 digests the food in the stomachs of animals, is of 

 this class. Of all the menstrua it is the most active, 

 the most universal. In the human stomach, for in- 

 stance, consider what a variety of strange sub- 

 stances, and how widely different from one another, 

 it in a few hours reduces to a uniform pulp, milk, 

 or mucilage. It seizes upon every thing ; it dis- 



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