400 INFLUENCE OF NERVES ON ABSORPTION. 



even mammalian blood-corpuscles (in the frog) were absorbed by the epithelial 

 cells of the intestine, and passed into the blood, are erroneous. Even for the 

 absorption of completely fluid substances, endosmosis and filtration seem to be 

 scarcely sufficient. An active participation of the protoplasm of the cells seems 

 here also in part at least to be necessary, else it is difficult to explain how very 

 slight disturbances in the activity of these cells e.g., from intestinal catarrh 

 cause sudden variations of absorption, and even the passage of fluids into the 

 intestine. 



If absorption was due to diffusion alone, when alcohol is injected into the 

 intestine, water ought to pass into the intestine, but this does not occur. Brieger 

 found that the injection of a - 5-l per cent, solution of salts into a ligatured loop 

 of intestine did not cause water to pass into the intestine; but it appeared when 

 a 20 per cent, solution was injected. 



193. Influence of the Nervous System. 



With regard to the influence of the nervous system upon intestinal 

 absorption we know very little. After extirpation of the semi-lunar 

 ganglion (Budge), as well as after section of the mesenteric nerves 

 (Moreau), the intestinal contents become more fluid, and are increased 

 in amount. This may be partly due to diminished absorption, v. 

 ThanhofFer states, that he observed the protrusion of threads from the 

 epithelial cells of the small intestine only after the spinal cord, or the 

 dorsal nerves, had been divided for some time. 



[Matthew Hay injected saline solutions directly into the exposed intestine. He 

 found that a 20 per cent, solution of sulphate of soda always excites a profuse 

 secretion, but that a 10 per cent, solution only does so, or rather, that it only 

 increases in bulk, when injected in sufficient quantity a certain weight of salt 

 failing to increase the bulk of the fluid secretion when dissolved as a 10 per cent, 

 solution, but exciting a profuse secretion when forming a 20 per cent, solution. Se- 

 cretion, he has reason to believe, is active in both perhaps, almost equally active 

 but absorption is greatly impeded in the'case of the concentrated salt, by its injurious 

 action on the absorptive mechanism of the mucous membrane. Moreau has recently 

 maintained that, under such circumstances, there is actually no absorption, but 

 Hay has disproved this, by observing that strychnia injected into a loop of intestine, 

 containing the concentrated salt, still causes death, although after an interval three 

 times longer than when the loop contains a 10 per cent, solution of the salt. 



Hay has also observed that the local effect of a ligature applied to the intestine 

 is to excite secretion from the mucous membrane in its immediate vicinity, and 

 therefore add to the bulk of the saline solution ; whereas the reflex effect of a 

 ligature, as exercised through the nervous system, is to diminish the quantity of 

 the secreted fluid in a remote portion of the intestine, probably by stimulating and 

 accelerating absorption. Division of the vagi does not affect the nature or the 

 quantity of the secretion]. 



194. Feeding with "Nutrient Enemata." 



In cases where food cannot be taken by the mouth e.g., in stricture of the 

 oesophagus, continued vomiting, &c., food is given per rectum (Celsus, 3-5 A.D.). 

 As the digestive activity of the large intestine is very slight, fluid food ought to 

 be given in a condition ready to be absorbed, and this is best done by introducing 



