LESSON XLVII 

 ABSORPTION 



OSMOSIS. INTESTINAL PERISTALSIS, SECRETION OF INTESTINAL 

 JUICE. ABSORPTION FROM THE SMALL INTESTINE 



1. Osmosis. Prepare an osmometer by tying a piece of fish condom 

 or other semipermeable membrane over the orifice of a thistle tube. 

 Fill the chamber of this tube with a concentrated solution of mag- 

 nesium sulphate. Fill a beaker with distilled water and suspend the 

 filled thistle tube in the water so that the levels of the fluids agree. 

 Attach a narrow glass tube, about 1 m. in length, to the end of the 

 thistle tube, and allow the apparatus to stand for twenty-four hours. 



FIG. 122. A SIMPLE OSMOMETER. 



The receptacle contains water, and the cell a solution of magnesium sulphate. As 

 the molecules of water are drawn through the semipermeable membrane the level of the 

 MgSO4 solution rises. 



Already in the course of an hour or two it will be observed that the level 

 of the solution of magnesium sulphate has risen a considerable distance. 

 The solution of magnesium sulphate possesses a greater osmotic press- 

 ure and draws molecules of water through the membrane. 



2. The Osmotic Power of the Intestine. Anesthetize a cat and 

 maintain the anesthesia until the animal has been killed by an overdose 

 of ether. Perform tracheotomy. Open the abdominal cavity by a 

 small longitudinal incision in the linea alba. Pull a loop of small in- 



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