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chyme by a mixture with the fluids added in the duodenum, may 

 be known by synthesis, that is, by mixing chyme with the biliary, 

 pancreatic, and mucous secretions, contributed by this part. 

 This may be done in the laboratory. The artificial product may 

 then ,be compared with the natural: some differences may be 

 found to depend upon temperature. Under an imitation of the 

 natural temperature, the chymical analysis, if it were sufficiently 

 perfect, would detect the presence or absence of combinations in 

 the artificial compound when compared with the natural product 

 of the intestine which are attributable to the want of that spiritual 

 agency, which will have a share in every process belonging to a 

 living body. 



7. This chymical investigation in the present state of our 

 information would most probably serve but to illustrate the ne- 

 cessity of the operation of that principle which has no substitute 

 in the laboratory, or, by shewing us how much may take place 

 without spiritual properties, to indicate what, or how much is ac- 

 complished by them. But as all this belongs to particular inquiry 

 with which I do not now profess to be engaged, I shall state the 

 history of the function in that imperfect way which will at least 

 render it conformable with the preceding views. 



8. In the progress of experiment, it may perhaps be decided 

 that the chymical changes which chyme undergoes, in order to 

 become chyle, may result from the combination of the former 

 with the intestinal fluids, &c.; or, it may be discovered, that an 

 approximation only to a similitude takes place between the natu- 

 ral chyle and that produced by an artificial mixture of the duo- 

 denal fluids with chyme. But, in a general view of the subject, it 

 does not appear necessary to decide upon this matter, since, by 

 tracing the agency a little higher, we shall find that both the al- 

 ternatives resolve themselves into one common inquiry. 



9. If the processes of the conversion we are considering are 

 but partially accomplished by the mixture of intestinal fluids with 

 chyme; or if this conversion takes place but imperfectly, under 

 circumstances similar to the latter, save that the principle of life 

 is extinct; then, that, the absence of which renders the conversion 

 imperfect, may be considered, when it exists, as a product of the 

 direct operation of vital properties upon the constituents of the 

 material with which they are related. But if the intestinal fluids 

 should be found capable, without the presence of a principle of 

 life, of accomplishing a perfect conversion (which is perhaps 

 scarcely to be, known), then the relation of the principle of life 

 with the constituents of chyme is mediate. The difference is, that 

 in the one case, (the direct) life produces changes in chyme, in 

 which the fluids do not co-operate; and in the other, that life pro- 

 duces fluids which accomplish the changes which chyme undergoes 

 in its conversion into chyle. I will not with our present facts 

 decide whether either of the relations just mentioned is exclusive, 

 or, if mixed, how much is assignable to each ; but after bestowing 



