LECT, IV. LAWS OF ABSORPTION. 87 



nal liquid which carries, in a given direction, the liquid 

 which has transversed the membrane.* 



Suppose for a moment that the direction of the circulation 

 of the blood was inverse to that which it really is, but with- 

 out any alteration in the structure and disposition of the 

 blood-vessels : we should then no longer say that the veins 

 absorbed, but, on the contrary, that absorption took place 

 by the arteries. Such is the very simple physical phenome- 

 non of this function. 



Laws of Absorption. I am anxious also to demonstrate 

 to you the laws of absorption, which were discovered by 

 experimental physiology ; and you will then readily perceive, 

 that they are the necessary consequences of the principles 

 which we have laid down. 



1st. " The more the matters are soluble, divided and 

 fitted for entering into combination with the organic juices, 

 and for becoming constituent parts of the blood, the more 

 easily are they absorbed." 



The language used in stating this law is not very scientific, 

 but I wish to give it to you as it is found in the most modern 

 accredited works on physiology. This law is an evident 

 consequence of the manner in which we have explained the 

 phenomenon of absorption. It is desirable that physiolo- 

 gists should study with attention the various degrees of 

 power with which different liquids are imbibed by organic 

 tissues, for such study will certainly prove highly important 

 to therapeutics. 



Let me show you some facts which will assist us in 

 understanding these researches. We have here two rabbits ; 



* This apparatus I have long been in the habit of using in the lecture 

 room, (see my Elements of Materia Medica.vol. i. p. 112, 2d edit., 1842.) 

 It is more convenient in practice to have the vein connected with the 

 bottle by a stopcock, as represented in the above figure, which differs in 

 this respect from the figure given jn Matteucci's lectures. J. P. 



