DIGESTION AND ABSORPTION. 191 



much NaCl has passed out of the dialyzer. An easy 

 and sufficiently accurate method is to evaporate to 

 dryness all, or a known proportion of the liquid in 

 the outer receptacle, and weigh the dry salt remain- 

 ing. How many grammes of water enterthe dial- 

 yzer for each gramme of salt that leaves ? (Endos- 

 motic equivalent.^ 



(3) Is the endosmotic equivalent constant for salt and 

 water? (a) Is it the same for different strengths 

 of the salt solution, i. e., for 10% or 1% as for 20%? 

 () Is it the same for two hours or four hours as 

 for one hour ? 



(4) Fill with 10% glucose three dialyzers provided with 

 three different kinds of membrane. Does osmosis 

 take place at the same rate in all three dialyzers ? 

 What is the endosmotic equivalent for glucose? 



(5) What is the endosmotic equivalent for dilute egg 

 albumin? When albumin is injected into the colon 

 it is readily absorbed as albumin, there being no 

 digestive changes in it. 



(6) Fill a dialyzer with equal parts of 10% glucose 

 and 10% NaCl. At the end of a convenient period, 

 2-6 hours, determine whether these substances have 

 diffused according to their own endosmotic equiva- 

 lents, i. e., independent of each other, or have they 

 been influenced the one by the other? 



(7) Fill a dialyzer with alcohol. Which way does the 

 osmotic current flow? 



(8) In the above experiments water has uniformly 

 passed into the dialyzer.* If pure water be taken 

 into an empty stomach would one expect it to be 

 readily absorbed ?| 



*If alcohol be taken into the stomach it is not diluted with water 

 drawn from the tissue, but it is rapidly absorbed. 



fWater is absorbed slightly, if at all, through the walls of the 

 stomach. 



