LYMPHATIC ABSORPTION. 619 



after division of the sciatic nerve in the hind limb of a guinea-pig, 

 aconite, which was not previously taken up through the skin, has been 

 found to be absorbed ; this has been attributed to the dilatation of the 

 smaller arteries, which follows section of the vasi-motor nerves. 

 (Waller.) Certain stimulating agents, such as chloroform and turpen- 

 tine, which favor absorption, may do so, by producing dilatation of the 

 bloodvessels, as is indicated by the increased redness of the surface to 

 which they are applied. It has been supposed that galvanism pro- 

 motes absorption, but the contrary seems to be the case. Heat, fric- 

 tion, and moisture, as well as exercise of a part, obviously favor 

 absorption ; whilst the opposite conditions of cold, rest, and absolute 

 dryness, disqualify a part from performing this function. 



The share of the process of general absorption due to the absorbent 

 vessels, i. e., to lymphatic absorption, is small. When the cuticle of 

 an animal is removed by blistering, and a solution of ferro-cyanide of 

 potassium is applied to the denuded cutis, though the poison may be 

 found in the veins, it has not been detected in the thoracic duct. Nev- 

 ertheless, even when the abdominal aorta and inferior vena cava of an 

 animal have been tied, to prevent the circulation of the blood through 

 the hinder limbs, and when, in addition to this, the internal iliac veins 

 have also been tied, to cut off the collateral circulation through the 

 veins of the pelvis, cyanide of potassium, and strychnine, inserted be- 

 neath the skin of the feet, even after the limbs have become rigid, have 

 been detected above the seat of the ligatures, and have produced char- 

 acteristic symptoms of poisoning ; the lymphatic vessels must here have 

 been the channels of absorption. In certain instances, morbid pro- 

 ducts are conveyed through lymphatic vessels, as, e.g., decomposed 

 animal fluids, pus, simple or specific, and also cancerous matter ; but 

 the extension of disease along the course of the lymphatics, and through 

 the lymphatic glands, may be sometimes due to the propagation of a 

 morbid process in the coats of the lymphatics. The coloring matter of 

 the bile has been seen in the lymphatics of the gall-bladder, after liga- 

 ture of the gall-duct, and consequent retention of the bile in its recep- 

 tacle. The subcutaneous lymphatics near tattooed portions of the skin, 

 are sometimes found charged with coloring matter, forming character- 

 istic ramified lines, differing in course from that of the bloodvessels. 

 Moreover, the identity of structure between the lymphatics and the lac- 

 teals, and the undoubted absorbent function of the latter, favor the con- 

 clusion that the former vessels likewise absorb. The termination of 

 all the lymphatics in the venous system, and the direction of the valves 

 in their interior, not only support this view, but enable us to deter- 

 mine the course and destination of their contents. 



The lymph, elsewhere described (p. 61), resembles chyle deprived of 

 its molecular basis, and of nearly all its fatty matter ; but its clear, 

 colorless, and limpid character, so unlike the milky opalescent aspect 

 of the chyle, renders it difficult of detection in its vessels during life. 

 Distended transparent lymphatics have, however, been seen on the sur- 

 face of the liver in recently killed animals, and the lymph itself has 

 been observed flowing from the cut surface of that organ, and also from 



