ORIGIN OF LYMPH. 309 



connective-tissues, contain more fluid after death than during life, while the blood-vessels have 

 given out a considerable amount of their plasma after death. 



(6) The amount of lymph is increased under the influence of curara, and so is the amount 

 of solids in the lymph (Lesser). A large amount of lymph collects in the lymph-sacs [especially 

 the sub-lingual] of frogs poisoned with curara, which is partly explained by the fact that the 

 lymph -hearts are paralysed by curara. The amount of lymph is also increased in inflamed 

 parts. 



200. ORIGIN OF LYMPH. (1) Source of the Lymph-Plasma. The 



lymph-plasma may be regarded as fluid which has been pressed through the walls 

 of the blood-vessels by the blood-pressure, i.e., by filtration into the tissues. The 

 salts which pass most readily through membranes, go through nearly in the same 

 proportion as they exist in blood-plasma the fibrin-factors to about two-thirds, and 

 albumin to about one-half of that in the blood. As in the case of other filtration- 

 processes, the amount of lymph must increase with increasing pressure. 



This was proved by Ludwig and Tomsa, who found that when they passed blood-serum under 

 varying pressures through the blood-vessels of an excised testis, the amount" of transuded fluid 

 which flowed from the lymphatics varied with the pressure. This " artificial-lymph " had a 

 composition similar to that of the natural lymph. Even the amount of albumin increased with 

 increasing pressure. The lymph-plasma is mixed in the different tissues with the decomposition 

 products, the results of the metabolism of the tissues. 



When the muscles act, not only is the lymph poured out more rapidly, but 

 more lymph is formed. The tendons and fascise of the muscles of the skeleton, 

 which are provided with numerous small stomata, absorb the lymph from the 

 muscles. By the alternate contraction and relaxation of these fibrous structures, 

 they act like suction-pumps, whereby the lymphatics are alternately filled and 

 emptied, while the lymph is propelled onwards. Even passive-movements act in 

 the same way. If solutions be injected under the fascia lata, they may be propelled 

 onwards to the thoracic duct by passive movements of the limb (Ludmg, Sckweigger- 

 Seidel). 



(2) The source of the lymph-corpuscles varies. (1) A very considerable 

 number of lymph-corpuscles are derived from the lymphatic glands ; they are 

 washed out of these glands into the vas efferens by the lymph-stream, hence, the 

 lymph always contains more corpuscles after it has passed through a lymph-gland. 

 Small isolated lymph-follicles permit corpuscles to pass through their limiting layer 

 into the lymph-stream. (2) Those organs whose basis consists of adenoid tissue, 

 and in whose meshes numerous lymph-corpuscles occur, e.g., the mucous membrane 

 of the entire intestinal tract, red marrow of bone, and the spleen ( 103). The 

 cells reach the origin of the lymph-stream by their own amoeboid movements. (3) 

 As lymph-corpuscles are returned to the blood-stream, where they appear as colour- 

 less blood-corpuscles, so they again pass out of the blood-capillaries into the 

 tissues, partly owing to their amoeboid movements, and they are partly expelled 

 by the blood-pressure. In rare cases lymph-corpuscles wander from lymphatic 

 spaces back again into the blood-vessels. 



Fine particles of cinnabar or milk -globules introduced into the blood soon pass into the lym- 

 phatics. The extrusion of particles is greater during venous congestion than when the circula- 

 tion is undisturbed, just as with diapedesis ( 95) ; inflammatory affections of the vascular wall 

 also favour their passage. The vessels of the portal system are especially pervious. 



(4) By division of the lymph-corpuscles, and also by proliferation of the fixed 

 connective-tissue corpuscles. This process certainly occurs during inflammation 

 of many organs. This has been proved for the excised cornea kept in a moist 

 chamber ; the nuclei of the cornea-corpuscles also proliferate. 



That the connective-tissue corpuscles proliferate is shown by the enormous production of 

 lymph -corpuscles in acute inflammations (with the formation of pus), e.g., in extensive erysipelas, 

 and inflammatory purulent effusions into serous cavities, where the number of corpuscles is 

 too great to be explained by the wandering of blood-corpuscles out of the blood-vessels. 



Decay of Lymph-Corpuscles. The lymph-corpuscles disappear partly where the 



