ABSORPTION 321 



the other hand, has a tendency to shrink or become dehydrated. He 

 showed that the arteries of the mesentery spread out into a capillary 

 network which lies directly under the intestinal epithelium and empties 

 into the portal vein as blood containing much carbonic acid. Ac- 

 cording to V. LIMBECK, A. GURBER and H. J. HAMBURGER red and 

 white blood corpuscles undergo an increase in volume of from 5 to 10 

 per cent when they enter the venous blood from the arteries. Ac- 

 cording to this, one liter of blood which passes through the intestine 

 would take up 17.5 c.c. of water even if we were to ascribe the ab- 

 straction of water to the blood corpuscles alone. From this fact, 

 M. H. FISCHER assumes that venous blood, so long as it is present 

 as such, absorbs water from the intestinal mucous membrane. 1 



Though the facts so far discovered seem so clearly to explain the 

 processes of absorption, we must not overlook the fact that they are 

 the result of experiments which have nothing in common with natural 

 taking of food, etc., by mouth. On this account, certain objections 

 have been raised. The living intestinal wall is not a closed tube but 

 one traversed by solutions, so that it is therefore a question whether 

 many phenomena are not quite different in the living animal. The 

 important discovery of LOEPER * must be mentioned : if salt solutions 

 of a given concentration are given by mouth, they are either concen- 

 trated or diluted so that they reach the intestines in approximately iso- 

 tonic condition. From a practical standpoint, all those conclusions 

 must be ignored which are based on the presence of hypotonic or hyper- 

 tonic salt solutions. 2 For the pharmacologic deductions see page 411. 



Within the intestine the osmotic pressure must vary greatly with 

 the enzymatic cleavage of the food, and it is impossible to under- 

 stand why at low osmotic pressures, salts of the blood, or crystal- 

 loid cleavage products of albumin might not diffuse back into the 

 intestine from the interior of the body. Based on the investiga- 

 tions of F. ABDERHALDEN, it is almost certain that colloidal albumin 

 is reconstructed from its cleavage products in the intestinal wall. 

 The intestinal wall functionates as a suction pump for the crystalloid 

 cleavage products of albumin which draws a stream of crystalloids 

 from the intestinal lumen in the direction of the interior of the body. 

 We may dismiss from consideration the absorption of albumins. 



1 In my opinion, FISCHER'S theory offers valuable aid in explaining nervous 

 influences upon processes of secretion and resorption. I might suggest that nervous 

 diarrheas may be attributed to increased arterial blood supply to the mesentery. 

 It is quite natural to regard diarrheas accompanying inflammatory processes in 

 the intestines as a consequence of the increased supply of arterial blood. 



2 In my opinion this does not exclude the fact that when introduced into the 

 intestines, the intestinal contents are usually hypertonic since crystalloids are 

 uninterruptedly formed as a result of digestion in the intestines. 



