3I2 ABSORPTION OF PARENCHYMATOUS EFFUSIONS. 



Waldeyer's ganglia. Stimulation of the skin, intestine, or blood-heart influences them reflexly 

 -partly accelerating and partly retarding them, [most frequently arresting them in diastole, 

 so^hat there seems to be 1 an inhibitory mechanism in the cord, but it is not affected by 

 atropine (Kabrhd).} If the coccygeal nerve, which connects the sacral hearts to the spinal 

 cord be divided, these effects do not occur. Strychnia accelerates their movements, and so 

 does heating of the spinal cord; but if the cord be cooled, they are retarded. A lymph -heart 

 arr.-sted bvbeinff exposed, or after the action of muscarm, can be caused to beat by falling it 

 under pressure, but this is not the case when the arrest is caused by destruction of its nerves. 

 Antiaria paralyses the lvmph-heart and the blood-heart at the same time, while curara 

 paralyses the former alone. In other amphibians, there are two lymph-hearts ; in the ostrich 

 and cassowary and some swimming birds, and in the embryo chick 1 or 2. They occur in some 

 fashes, c.fj., near the caudal vein of the eel. 



(7) The nervous system has a direct effect upon the lymph-stream, on account 

 of its connection with the muscles of the lymphatics and lymph-glands, and with 

 the lymph-hearts where these exist. Kiihne observed that the cornea corpuscles 

 contracted when the corneal nerves were stimulated, [and Hoffman has described the 

 termination of nerves in connective-tissue corpuscles]. Goltz also observed that, 

 when a dilute solution of common salt was injected under the skin of a frog, it was 

 rapidly absorbed, but if the central nervous system had been destroyed, it was not 

 absorbed. 



If inflammation be produced in the hind legs of a dog, and if the sciatic nerve be divided on 

 one side, oedema and a simultaneous increase of the lymph-stream occur on that side. ^ [A 

 combination of congestion and inflammation greatly increases the lymph-stream, and this is 

 still more the case when the nerves are divided at the same time.] 



Ligature the leg of a frog, except the nerves, so as to arrest the circulation, and place the 

 leg in water ; it swells up very rapidly, but a dead limb does not swell up. So that absorption 

 is independent of the continuance of the circulation. Section of the sciatic nerve, or 

 destruction of the spinal cord (but not section of the brain), arrests absorption. 



202. ABSORPTION OF PARENCHYMATOUS 'EFFUSIONS. Fluids which pass from the 

 blood-vessels into the spaces in the tissues, or those injected subcutaneously, are absorbed 

 chiefly by the blood-vessels, but also by the lymphatics. Small particles, as after tattooing 

 with cinnabar or China ink, may pass from the tissue-spaces into the lymphatics and so do 

 blood-corpuscles from extravasations of blood, and fat-granules from the marrow of a broken 

 bone. If all the lymphatics of a part are ligatured, absorption takes place quite as rapidly as 

 before ; hence, absorbed fluid must pass through the thin membranes of the blood-vessels. The 

 corresponding experiment of ligaturing all the blood-vessels, when no absorption of the paren- 

 chymatous juices takes place, does not prove that the lymphatics are not concerned in absorp- 

 tion, for, after ligaturing the blood-vessels of a part, of course the formation of lymph, 

 and also the lymph -stream, must cease. "When fluids are injected under the skin, absorption 

 takes place very rapidly more rapidly than when the substance is given by the mouth. The 

 subcutaneous injection of drugs is extensively used, but of course the substances used must 

 not corrode, irritate, or coagulate the tissues. Some substances do not act when given by 

 the mouth, as snake poison, poisons from dead bodies, or putrid things, although they act 

 rapidly when introduced subcutaneously. If emulsin be given by the mouth, and amygdalin 

 be injected into the veins of an animal, hydrocyanic acid is not formed, as the emulsin seems 

 to be destroyed in the alimentary canal. If the emulsin, however, be injected into the blood, 

 and the amygdalin be given by the mouth, the animal is rapidly poisoned, owing to the forma- 

 tion of hydrocyanic acid, as the amygdalin is rapidly absorbed from the intestinal canal. The 

 amygdalin, a glucoside (C 20 H 27 NO n ), is acted upon by fresh emulsin like a ferment ; it takes* 

 up 2(H 2 0) and yields hydrocyanic acid (CHN), + oil of bitter almonds (C 7 H tt O), + sugar 

 2(C d Hi 2 6 ). Serum injected subcutaneously is rapidly absorbed; it is decomposed within the 

 blood-stream, and increases the amount of urea. Albuminous solutions, oil, peptones, and 

 sugars are also absorbed. 



203. (EDEMA, DROPSY, AND SEROUS EFFUSIONS. [Dropsy. As aptly illustrated 

 by Lauder Hrunton, the lymph-spaces may be represented by cisterns, each of which is 

 provided -with supply pipes the arteries and capillaries ; while there are two exit pipes the 

 veins and lymphatics. In health, the balance between the inflow and outflow is such that the 

 spaces are merely moistened with fluid. When a cannula is placed in a lymphatic vessel in a 

 dog, only a few drops of lymph flow out at long intervals, but if the veins of the limb be ligatured, 

 the lymph flows much more quickly. This is in part due to the increased transudation of fluid 

 from the small blood-vessels, but it may also be due to fluid passing away by the lymphatics 

 when it can no longer be carried away by the veins. We cannot say what is the relative share 

 of the veins and the lymphatics, nor in the above experiment do we know how much is due to 





