191 



by a foreign cause, involves the natural or regular dependent com- 

 municated properties ; or whether it is produced by others, arising 

 out of a new condition, so far distinct from the natural, that the 

 medium of communication subsisting, the secondary affection may 

 occur where there was no natural communication of properties of 

 the regular kind. 



25. In addition to the analysis of chyle, which has been sug- 

 gested for the purpose of enabling us by an artificial combination of 

 the constituents detected to decide whether even all the perceptible 

 phenomena of the conversion are dependent upon chymical agents, 

 there remains to be remarked, in the chymical department, the pre- 

 cise share or import which each secretion has in the common result. 

 Thus, it is to be inquired, how much of the conversion is performed 

 by the constituents of intestinal mucus; how much by the biliary; 

 and how much by the pancreatic secretions. This investigation is 

 to be prosecuted not merely with a view to the general result of 

 the combination of one or more of these fluids with chyme, but 

 relations of constituents are to be sought after, and the combina- 

 tions and changes among them to be specified, and this respectively 

 according to the threefold division of the spiritual, chymical, and 

 mechanical departments. Such an inquiry, to the extent permitted 

 by the imperfect means of analysis which we possess, is not difficult; 

 but this same imperfection in the means of analysis would most pro- 

 bably render it of no value. 





