LYMPHATIC VESSELS 



141 



LYSOZYME 



sight it may be difficult or impossible to 

 see any lymphatics 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. 182-4) 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 Lymphoid Tissue. 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, 443-44G. 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 hydrokoUag 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 

 chambers in the ears of rabbits (Clark, 

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

 62, 59-92. See India ink method for 

 renal lymphatics (Pierce, C. E. 2nd., 

 Anat. Rec, 1944, fiO, 315-329). 



Lyons Blue, see Spirit Blue. 



Lymphocytes. There is no specific stain 

 for lymphocytes, but identification is 

 usually easy at least for small lympho- 

 cytes. To observe motility, mount 

 fresh blood and ring with vaseline to 

 prevent evaporation. Movements 



usually begin after the neutrophiles 

 have become active. Examination in 

 the darkfield may be helpful. Mito- 

 chondria can be demonstrated easier 

 in lymphocytes by supravital staining 

 with Janus Green than in polymorpho- 

 nuclear leucocytes because they are not 

 obscured by the specific granulations. 

 In the study of smears the characteristic 

 cytoplasmic basophilia of lymphocytes 

 can be brought out by most of the usual 

 stains (Giemsa's, Wright's). The 

 Peroxidase Reaction of lymphocytes is 

 negative, or very strictly limited. 

 Methods demonstrating Cathepsin, Nu- 

 clease, Amylase, Lipase, Lysozyme and 

 Adenosinase in lymphocytes are de- 

 scribed by Barnes, J. M., Brit. J. Exp. 

 Path., 1940, 21, 264-275. To determine 

 the age of lymphocytes is extraordinarily 

 difficult. Perhaps the nearest approach 

 to this goal is the work of Wiseman, 

 B. K., J. Exper. Med., 1931, 54, 270-294. 



Lysis. In histology this term means the 

 solution of a cell resulting from injury 

 to the cell membrane. A choice may 

 be made of several agents productive 

 of this change. As classified by Danielli 

 (Bourne, pp. 74-75) antibodies and 

 polyhydroxylic phenols probably act 

 almost wholly on the protein component 

 of the membrane; lipoid solvents, 

 lecithinase, digitonin, sodium or potas- 

 sium salts of fatty acids and paraffin 

 sulphonates mainly on the lipoid part; 

 and the heavy metals probably on both. 

 He suggests the probable modes of 

 action. It is therefore possible tliat 

 these lytic agents may in their action 

 provide clues as to the nature of the 

 plasma membrane. See Cell Mem- 

 branes. 



Lysozyme a heat and acid resistant enzj^me 

 produced from egg white and isolated 

 as a basic protein of small molecular 

 weight by Abraham, E. P., Biochem. 

 J., 1939, 33, 622-030. It is present in 

 many animal and plant tissues. A 



