On Intestinal Absorption. 



95 



3. No evidence can be obtained of specific absorptive fibres in the 

 mesenteric nerves. 



4. The state of nutrition of the cells is the main factor in their 

 activity, and this is intimately associated with the blood supply. 



5. In reduction of the rate of absorption, without detachment of 

 epithelium, the absorption of the various constituents of serum is 

 reduced in the proportion in which they exist in the original fluid. 



6. The activity of the cells may be raised by stimulation with weak 

 alcohol, without evidence of concomitant increase of blood supply. 



7. The bile has no stimulant action on the cells. 



8. The cells exhibit an orienting action upon salts in solution (sodic 

 chloride especially). In a loop of gut with injured cells sodic chloride 

 enters the lumen from the blood, at a time when it is being actively 

 absorbed from a normal control loop in the same animal. (This fact 

 was first noted by 0. Cohnheim.) 



9. The absorption of water from solutions introduced into the gut 

 is dependent upon -two factors : — 



(a) The physical relation of the osmotic pressure of the solution in 



the gut to the osmotic pressure of the blood plasma. 



(b) The physiological regulation of the difference of osmotic pres- 



sure by the orienting mechanism of the cells. 



10. The chief factor in the absorption of peptone is an assimilation 

 (or adsorption) by the cells, while in the absorption of glucose, diffu- 

 sion, variable by the permeability of the cells (and so, probably, related 

 to their physiological condition) is the main factor. 



11. By removal of the epithelium, the normal ratio of peptone to- 

 glucose absorption is upset, and the value tends to approach that of 

 diffusion of these substances through parchment paper into serum. 



12. Absorption in the lower ileum is greater for the organic solids 

 of serum, and less for peptone and glucose than in the upper ileum. 

 The relative absorption of water in the upper and lower ileum is. 

 variable. 



13. The relative impermeability of the lower ileum to glucose dis- 

 appears with removal of the epithelium. 



14. Absorption in the colon is for all constituents of serum, and for 

 peptone and glucose far less per unit of measured surface than in the 

 middle region of the ileum. 



15. The normal relative excess of salt absorption from serum over 

 water absorption, observed throughout the intestine, is most marked in 

 the colon, and more marked in the lower than in the upper ileum. 



16. Finally it is suggested that the cell activity which causes serum 

 to pass over to the blood is of the same nature as that involved in the 

 orienting action of the cells upon salts in solution. 



VOL. LXY. 



H 



