CHAP. XXVI.] FUNCTION OF THE ABSORBENTS. 289 



walls for the nutrition of the tissues, may have its superfluous 

 parts removed through the lymphatics, as it would, perhaps, be 

 more readily received into these new channels than into the same 

 from which it had just been poured. It is a question quite unde- 

 termined, whether the effete materials of the tissues are returned to 

 the circulation in any large measure through the lymphatics, or 

 whether they are principally restored to it by directly entering the 

 capillaries, in exchange for that outgoing current of renovating 

 plasma which serves to supply the waste in nutrition. The car- 

 bonic acid at least, if indeed that product be formed among the 

 tissues, outside the capillaries, and not in the blood, seems to enter 

 the capillaries in a direct manner through their wall, since it is 

 found in greater quantity in venous than in arterial blood. 



The absorbent system, with its glands, may be regarded in yet 

 another light, viz., as a great internal glandular or secreting system, 

 the ducts of which open not on the surface of the body, but into the 

 vascular system. It is conceived that the inner surface of the 

 lymphatics, and especially of the lymphatic glands, serves to elabo- 

 rate and separate from the blood contained in the vessels distributed 

 on their walls a secretion which is set free into their interior, and is 

 transmitted ultimately to the current of circulating blood through 

 the efferent vessels of the glands, which may be thus looked upon 

 as excretory ducts. Some physiologists attach much importance 

 to the alleged increase in the quantity of fibrine contained in the 

 lymph as it traverses the absorbent system, and conclude that this 

 is due to the elaborating agency of the epithelial element of the 

 absorbent tracts on the albumen of the lymph. We owe to Dr. 

 Carpenter a very interesting hypothesis on the influence, in this 

 respect, of the colourless corpuscles, which he imagines to exert 

 this catalytic action on the albumen in which they float. This idea 

 will be best considered in the Chapter on the Blood. 



On the subjects of the foregoing chapter, in addition to the systematic 

 works on Physiology before referred to, the student may consult Mr. Lane's 

 article " Lymphatic System," in the Cyclopaedia of Anatomy and Physiology ; 

 Matteucci's " Lectures on the Physical Phenomena of Living Beings," trans- 

 lated by Pereira ; and the valuable " Reports " by Mr. Paget, in the British 

 and Foreign Medical Review. We would also refer to a recent work by Liebig, 

 on the motion of the juices of the animal body, ably translated by Dr. Gregory, 

 from which we have derived much assistance. 



