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CHAP. III. The Intestines. 



1. THE perceptible changes which food undergoes in 

 these organs need not be enumerated. It is designed only to 

 point out briefly the objects of investigating their function; and to 

 exhibit their relations as a part of those general ones, making a 

 system, to which they belong. 



2. It is the business of analysis to specify in what consists 

 the difference between chyle and chyme. The changes which 

 food sustains in its conversion into chyme are supposed to some 

 extent to have been ascertained. A similar investigation belongs 

 to every portion of the intestinal canal, the effect of the function 

 of which is to produce new changes. Thus, it is to be asked 

 severally of the chymical changes sustained by that which was 

 originally food, in the duodenum, the jejunum, the ileum, the 

 cecum, the colon, the rectum; and perhaps the same question may 

 apply to the several parts of each. 



3. The chyraical differences assigned, as they may be to some 

 extent (the mechanical scarcely furnishing a topic of inquiry), it is 

 the further business of analysis to specify the vital changes which 

 are also produced in the same seats. 



4. The spiritual changes are in truth the principal objects of 

 the several functions : for the final purpose of every stage of the pre- 

 paration which food sustains is that it may become a material, the 

 elementary life of which may be so related with the diffused formal, 

 that the former may be capable of supporting the latter, and of 

 contributing towards those phenomena of the structures which are 

 connected with, or dependent upon, spiritual assimilation. 



5. I say then that it is the business of analysis, no less to 

 settle these spiritual changes than to remark the grosser cbymical 

 differences ; which latter will never be in any great degree explana- 

 tory of an animal process. But to specify these subtile changes 

 would require that other sense, of which we have before regretted 

 the want. Since then in this case, as in that of the stomach, we 

 can only particularize that which we desire, rather than that which 

 we are at present qualified to attain, we must \)p content with in- 

 quiring more generally and distantly into these processes, 



6. The intestinal material of nutrition is mixed with the 

 secretions of the structure, and with those of adjoining glands. 

 The chymical differences (or at least some of them) produced on 

 c c 



