TREATMENT. 133 



If to the water ia the vessel there be added salt enough to 

 make it of the same saline strength as that in the tube ; in 

 an equally short time, the fluid in the latter will go back to 

 its original level. But if again, more salt be dissolved in 

 the vessel, the fluid in the tube will soon be found at a lower 

 point. The law of these changes of level may be thus 

 expressed." 



" The spring water flows towards the saline water, and the weaker 

 solution of salt towards the stronger ; as if forced by an external 

 pressure to pass through the pores of the membrane, in opposition to 

 the la\^ of gravitation."* 



Water also flows towards Moody when into the tube is 

 poured ox-blood, deprived of its fibrine, and the experiment 

 is conducted in the presence of water heated to blood heat 

 or 100^ Fahr. But this flow is dependent upon the existence 

 of salt in the liquor sanguinis. 



If again to either fluid, as in the original experiments, 

 there be added a free alkali (carbonate or phosphate), the 

 change in level is more rapidly produced. And finally, if 

 the outer liquid be made slightly acidv then 



" the flow of the acid to the alkaline liquid takes place with the 

 greatest velocity." 



The philosophy of digestion in the flow of the alkaline 

 fluids of the blood toward the stomach, which, when distended 

 with food, secretes an acid, and the general percolation of 

 fluids through the membranes of the body find an easy 

 illustration in these experiments. The latter may also ex- 

 plain how an acid judiciously selected and employed so as 

 not to impair the susceptibility of the membranes, may be 

 so moved by the swift propulsion of osmose, as not only to 

 neutralize the alkali in excess, but also to arrest the attend- 

 ant decomposition. But aside from such conjectural views, 

 we have at this time a practical purpose in drawing attention 

 to the action of saline drugs. When these are introduced 

 into the alimentary canal, to induce catharsis, the flow 

 of fluids not so highly charged with saline ingredients, — 



* Liebig's Letters, p. 430. 



