CHAP. XXV.] FUNCTION OF THE PANCREAS. 245 



of molecular matter, as well as red and white blood corpuscles. 

 The contents of the intestine were more or less acid throughout, 

 and abundantly coloured by bile. There were very numerous 

 white flocculi, most conspicuous in the duodenum, and becoming 

 gradually less numerous to within an inch or two of the co3cum, 

 where they ceased. These flocculi consisted of an abundance of 

 granular matter, with columnar epithelium, having the free ends 

 of the particles filled with minute oil-globules, while the neighbour- 

 ing epithelium contained no oily matter. The villi were mostly 

 stripped of their epithelial sheaths, or held them very loosely; 

 the intra-villous structure was opaque, and the vesicular structure 

 beneath the basement membrane at their free extremities was very 

 distinct. 



It was evident, in these experiments, that the marked contrast 

 between the state of the contents of the lacteals, and the condition 

 of the villi, was connected with the presence or absence of fat in the 

 food, and that so long as the food was purely albuminous or fibrin- 

 ous, or mainly amylaceous, the chyle was transparent, and the 

 villi apparently inactive ; but that the addition of fat to the food 

 called the villi into activity, and filled the lacteals with an abun- 

 dant milky chyle. 



Are we to infer, then, that the lacteals absorb fatty matters only, 

 and that the villi are altogether inactive, save when fatty or oily 

 substances are to be absorbed? We apprehend that such an 

 inference is not justifiable ; it may, however, be concluded that the 

 villi and the lacteals are capable of absorbing all substances which 

 the blood-vessels absorb, and by a simple process ; but that the 

 absorption of fatty matters devolves upon them only, and is a more 

 complex process, involving considerable changes in their tissue. 



And upon similar grounds, we may conclude that while albuminous 

 and fibrinous aliments contribute to the formation of chyle, they 

 do not necessarily undergo the change into chyle in order to be 

 absorbed. But fatty matters appear to admit of absorption in no 

 other way, except by a reduction to the state of molecular base of 

 the white chyle. 



The observations and experiments denote, sufficiently clearly, 

 that two channels exist for the transmission of the nutritious mat- 

 ters from the intestines to the blood ; one through the lacteals by 

 the villi ; the other directly through the walls of the blood-vessels 

 themselves. Matters taking the latter route must pass through the 

 liver, and would be subjected to the influence of that gland before 

 they reach the inferior vena cava and the right auricle, while those 



