cxc LYMPHATIC SYSTEM. 



It is not unreasonable to presume that, in the proper glandular substance, there is 

 a continual production of lymph-corpuscles, most probably by fissiparous multiplica- 

 tion, which pass into the lymph-sinus, and that fresh corpuscles are thus added to the 

 lymph as it passes through a gland ; and this view is supported by the fact, that the 

 corpuscles are found to be more abundant in the lymph or chyle after it has passed 

 through the glands (see page L). It has been alleged, moreover, that the lymph, 

 after passing the glands, is richer in fibrin, and therefore coagulates more firmly. In 

 any case, it is plain that the numerous blood-capillaries distributed in a gland must 

 bring the blood into near relation with the elements of the lymph; and the latter 

 fluid, as it must move very slowly through the relatively wide space within the gland, 

 is thus placed in a most favourable condition for some not improbable interchange of 

 material with the blood. 



Termination. The absorbeut system discharges its contents into the 

 veins at two points, namely, at the junction of the subclaviau and internal 

 jugular veins of the left side by the thoracic duct, and at the corresponding 

 part of the veins of the right side by the right lymphatic trunk. The 

 openings, as already remarked, are guarded by valves. It sometime i 

 happens that the thoracic duct divides, near its termination, into two or 

 three short branches, which open separately, but near each other ; more 

 rarely, a branch opens into the vena azygos indeed the main vessel has 

 been seen terminating in that vein. Again, it is not uncommon for larger 

 branches, which usually join the thoracic duct, to open independently in 

 the vicinity of the main termination ; and this is more apt to happen with 

 the branches which usually unite to form the right lymphatic trunk. By 

 such variations the terminations in the great veins are multiplied, but still 

 they are confined in man to the region of the neck ; in birds, reptiles, and 

 fish., on the other hand, communications take place between the lymphatics 

 of the pelvis, posterior extremities and tail, and the sciatic or other con- 

 siderable veins of the abdomen or pelvis. 



The alleged terminations of lymphatics in various veins of the abdomen, described 

 by Lippi as occurring in man and mammalia, have not been met with by those who 

 have since been most engaged in the prosecution of this department of anatomical re- 

 search, and accordingly his observations have generally been either rejected as 

 erroneous, or held to refer to deviations from the normal condition.* But, while such 

 (extraglandular) terminations in other veins than those of the neck have not been 

 generally admitted, several anatomists of much authority have maintained that the 

 lacteals and lymphatics open naturally into veins within the lymphatic glands. This 

 latter opinion, which has been strenuously advocated by Fohnaann in particular, is 

 based on a fact well knoAvn to every one conversant with the injection of the 

 vessels in question, namely, that the quicksilver usually employed for that purpose, 

 when it has entered a gland by the inferent lymphatics, is apt to pass into branches of 

 veins within the gland, and thus finds its way into the large venous trunks in the 

 neighbourhood, in place of issuing by the efferent lymphatic vessels. But, although 

 it, of course, cannot be doubted that, in such cases, the mercury gets from the 

 lymphatics into the veins, no one has yet been able to perceive the precise mode in 

 which the transmission takes place ; and, looking to the circumstances in which it 

 chiefly occurs, it seems to be more probably owing to rupture of contiguous lymphatics 

 and veins within the glands, than to a natural communication between the two classes 

 of vessels in that situation. 



Lymphatic heart*. Miiller and Panizza, nearly about the same time, but inde- 

 pendently of each other, discovered that the lymphatic system of reptiles is furnished, 

 at its principal terminations in the venous system, with pulsatile muscular sacs, 



* In a communication inserted in Miiller's Archiv for 1848, p. 173, Dr. Nutm, of 

 Heidelberg, affirms the regular existence of these abdominal terminations, and refers to 

 three instances which he met with himself. In two of these, the lymphatics opened into 

 the renal veins, and in the other into the vena cava. 



