WATER AND SALINE SOLUTIONS. 61 



Finally, if we drink a solution containing rather Solution 



* f containing 



more salt than the blood, a more or less decided more salt 



than the 



catharsis ensues. blood. 



The action of solution of salt is of three kinds, 

 according to the proportion of salt. Spring water is 

 taken up into the blood-vessels with great rapid- 

 ity ; while these vessels exhibit a very small power 

 of absorption for water containing the same pro- 

 portion of salt as the blood does ; and a still more 

 strongly saline solution passes out of the body not 

 through the kidneys, but through the intestinal 

 canal. 



Saline solutions and water, given in the form of Enemata of 

 enemata, exhibit similar phenomena in the rectum. Sine ^iu- 

 Pure water is very rapidly absorbed, and excreted 

 through the urinary passages. If we add to the 

 water coloured or odorous matters, these appear, 

 more or less changed in the urine. When a small 

 quantity of ferrocyanide of potassium is added, its 

 presence in the urine is very soon detected by chlo- 

 ride of iron, which forms with it Prussian blue. Of 

 concentrated solutions far less is absorbed in the 

 same time, than of diluted ; in most cases they mix 

 with solid matters collected in the rectum, and are 

 expelled in the form of a watery dejection. 



All salts do not act alike in this respect. In Salts differ 

 equal doses, the purgative action of Glauber salt respect. 

 and Epsom salt is far stronger than that of sea salt ; 

 and their power of being absorbed by animal mem- 

 branes appears to be in the inverse ratio of this 



