PREFACE. 



THE present little work contains a series of ex- 

 periments, the object of which is to ascertain the 

 law according to which the mixture of two liquids, 

 separated by a membrane, takes place. The reader 

 will, I trust, perceive in these researches an effort 

 to attain, experimentally, to a more exact expression 

 of the conditions under which the apparatus of the 

 circulation acquires all the properties of an apparatus 

 of absorption. 



In the course of this investigation, the more inti- 

 mate study of the phenomena of Endosmosis im- 

 pressed on me the conviction that, in the organism 

 of many classes of animals, causes of the motion of 

 the juices were in operation, far more powerful than 

 that to which the name of Endosmosis has been 

 given. 



The passage of the digested food through the 

 membranes of the intestinal canal, and its entrance 

 into the blood ; the passage of the nutrient fluid 

 outwards from the blood-vessels, and its motion 



