LUTECIUM 



186 



LYMPHATIC VESSELS 



C. C. Macklin, Dept. of Histological 

 Research, The University of Western 

 Ontario, London, Canada. November 

 28, 1951— This may be done (1) by 

 prompt immersion of the fresh flayed 

 intact thorax (IIT) in any good fixative 

 which is adaptable to small animals, 

 such as mice; (2) by perfusion of the 

 blood vessels of the intact thorax of the 

 recently exsanguinated animal (PIT); 

 (3) by injection of the fixative into the 

 trachea with the thorax unopened 

 (BF). This is known as bronchial 

 filling. For technique of methods Nos. 

 1 and 2 see Dust Cells. For method 

 No. 3 a cannula is tied into the trachea 

 and fixing fluid injected in amount equal 

 to one-third to one-half of the volume 

 of the lung in full expiration. Presence 

 of air does not prevent spread. Fix- 

 ation is rapid. After tying the trachea 

 the preparation is allowed to stand one 

 to twenty-four hours. This method 

 may be combined with No. 1. Methods 

 1 and 3 may be used without previous 

 exsanguination. In methods 1 and 2 

 the capillaries of the alveolar walls are 

 fully opened, but in 3 they are only 

 partly so. Methods 1 and 2 possess the 

 advantage of not having loose particles 

 washed into the lower part of the air 

 tract. Other advantages are con- 

 sidered under "Dust Cells". Methods 

 1 and 2 demonstrate the close and ex- 

 tensive relation of the capillaries of the 

 alveolar wall to the pneumonocytes 

 (Macklin, C. C, Trans. Roy. Soc. of 

 Can., Sect. V, 1946, 40, 93-111). 



Lutecium, see Atomic Weights. 



Lutein, see Lillie, p. 129. 



Luyet, see Revival after Ultra Rapid Cooling. 



Lymphatic Vessels. There are many ways 

 of demonstrating lymphatic vessels. 

 The most convenient is to sit in an easy 

 chair and view the splendid moving 

 picture prepared by Dr. Richard L. 

 Webb of the Department of Anatomy of 

 the University of Illinois College of 

 Medicine entitled: "Mesenteric lym- 

 phatics, their conduct and the behavior 

 of their valves in the living rat". 



Another easy method is to watch 

 absorption of cream in a cat. A fasting 

 animal is fed | pint of cream and the 

 abdominal cavity is opened under ether 

 anesthesia a few minutes later. At first 

 sight it may be difficult or impossible to 

 see any lyroplmtics in the mesentery 

 although a few bean shaped lymph nodes 

 are visible near its base and can be 

 easily felt. Keep the abdominal con- 

 tents moist with saline. Close the 

 opening. In a little while, when again 

 examined, the lymphatic vessels will be 

 clearly marked in white by the milk fat 



which has been absorbed by the lacteals 

 and is being transported in them. 



A simple method to visualize the 

 pathways of lymphatic drainage from 

 the nasal mucous membrane has been 

 described by Yoffey, J. M., Lancet, 

 1941, 1, 529-530. Anesthetize a cat. 

 Drop into each nostril 1 cc. 5% trypan 

 blue (T. 1824) in physiological saline 

 (0.85% aq. NaCl). T. 1824 is specified 

 because it is a trypan blue isomer which 

 is deeply colored even in high dilutions 

 but any good trypan blue will do. Dis- 

 sect away the side of the neck. 

 Lymphatic vessels, deeply stained, will 

 be seen from the nose and pharynx 

 converging to the deep cervical node 

 and from the posterior border of this 

 node a single deep cervical vessel takes 

 origin and proceeds downward in the 

 neck. The technique delineates a func- 

 tioning system of vessels actually at 

 work. 



Lymphatic vessels and capillaries 

 constitute a drainage system provided 

 in largest measure beneath the external 

 surface of the body and the invagina- 

 tions of this surface into it in the respira- 

 tory, alimentary and urinogenital 

 systems. They are absent in the 

 brain and bone marrow and rare or 

 absent in skeletal muscle. See detailed 

 information concerning the organ or 

 tissue, in which it is desired to demon- 

 strate them, to be found in Drinker, 

 C. K. and Yoffey, J. M., Lymphatics, 

 Lymph and LymphoidTissue. Harvard 

 Univ. Press, 1941, 406 pp. 



Methods for the injection of lympha- 

 tics involve forcing fluid containing 

 particulate matter into areas where 

 there are many lymphatic capillaries. 

 A technique for the observation in vivo 

 of the superficial lymphatics of human 

 eyelids is described by Burch, G. E., 

 Anat. Rec, 1939, 73, 443-446. 0.02 cc. 

 of a dilute solution of patent blue V is 

 injected intradermally 5-10 mm. beyond 

 the middle of the lid margin. The 

 lymphatics are apparent in about 5 

 min. and may be observed as long as 

 75 min. Consult earlier experiments 

 with this dye by McMaster, P. D., 

 J. Exp. Med., 1937, 65, 347-372. 



A good way is to utilize the trans- 

 parent ears of white mice to inject the 

 lymphatics with hydrokollag by means 

 of a microdissection apparatus (Pul- 

 linger, B. D. and Florey, W. H., Brit. J. 

 Exp. Path., 1935, 16, 49-61). But the 

 best available technique is closely to 

 examine over long periods of time living 

 non-injected lymphatics in Sandison 

 cliambers in the ears of rabbits (Clark, 

 E. R. and E. L., Am. J. Anat., 1937, 

 62, 59-92. See India ink method for 



