538 ABSORPTION. 



The ordinary corpuscular elements of the lymph leuco- 

 cytes and globulins are also found in variable quantity in 

 the chyle. These have already been fully considered. 



Movements of the Lymph and the Chyle. 



Compared with the current of blood, the movements of 

 the lymph and chyle are feeble and irregular ; and the char- 

 acter of these movements is such that they are evidently due 

 to a variety of causes. As regards those elements which are 

 derived directly from the blood, the lymph may be said to 

 undergo a true circulation ; inasmuch as there is a constant 

 transudation at the peripheral portion of the vascular system 

 of fluids which are returned to the circulating blood by the 

 communications of the lymphatic system with the great 

 veins. But we have seen that the lymph is not derived en- 

 tirely from the blood, a considerable portion resulting from 

 interstitial absorption in the general lymphatic system, and 

 from the absorption of certain nutritive matters by the chy- 

 liferous vessels. These are, physiologically, the most impor- 

 tant constituents of the lymph and chyle ; and they are 

 taken up simply to be carried to the blood, and do not pass 

 again from the general vascular system into the lym- 

 phatics. 



As far as the mode of origin of the lymph and chyle has 

 any bearing upon the movements of these fluids in the 

 lymphatic vessels, there is no difference between the imbibi- 

 tion of new materials from the tissues or from the intestinal 

 canal, and the transudation of the liquid portions of the 

 blood ; for the mechanism of the passage of liquids from the 

 blood-vessels is such that the motive power of the blood can- 

 not be felt. An illustration of this is in the mechanism of 

 the transudation of the liquid portions of the secretions. The 

 force with which fluids are discharged into the ducts of the 

 glands is enormous, and is independent of the action of the 

 heart ; being due entirely to the force of transudation and 

 secretion. This is combined with the force of imbibition, 



