TRACHEA 



351 



TRANSPARENT CHAMBER 

 TECHNIQUE 



preparations of Sarcocystis and En- 

 cephalitozoa. 



Trachea. Excellent experimental methods 

 to demonstrate secretion of Mucus 

 are detailed by Florey, H., Carleton, 

 H. M. and Wells, A. Q., Brit. J. Exper. 

 Path., 1932, 13, 269-284. Techniques 

 for Nerve Endings are given under this 

 heading but it would be helpful to con- 

 sult Larsell, O. and Dow, R. S., Am. J. 

 Anat., 1933, 52, 125-146 who illustrates 

 what one may expect to find. Tech- 

 niques for Cilia require no special 

 adaptation. Celloidin sections are 

 smoother than paraffin ones. 



Tracer Techniques, see Radioactive Isotopes. 



Trachoma Bodies. These are easily colored 

 by Giemsa's stain. For demonstration 

 of glycogen in them and other pertinent 

 data see Thygeson, P., Am. J. Path., 

 1938, 14, 455-462. 



Evolution forms of Rickettsia tra- 

 chomatis. Fix smears in iodine alcohol, 

 4-5 min. Stain in May-Griinwald, 1 

 part; Giemsa, 1 part; neutral aq. dest. 

 10 parts for 1 hr. Differentiate in 95% 

 alcohol (Foley, H. and Parrot, L., Arch. 

 Inst. Pasteur d'Alg^rie, 1938, 16, 283- 

 292) . See colored plates by the authors. 



Transplantation. This technique provides 

 opportunities for important microscopic 

 studies. See Anterior Chamber of 

 Eye, Chorioallantoic Membrane, Or- 

 gan Culture, Tissue Culture, and Tooth 

 Germs. 



Transparent Chamber Technique — Writ- 

 ten hj Eliot R. Clark, Department of 

 Anatomy, University of Pennsylvania, 

 and Wistar Institute of Anatomy and 

 Biology, Philadelphia, Pa. Novem- 

 ber 28, 1951 — Several types of trans- 

 parent chambers and windows have 

 been developed, that have been inserted 

 in the outer ears, and in other locations, 

 of rabbits and other animals, with the 

 aid of which it is possible to watch 

 through the microscope — ^in some types 

 of chambers with the oil immersion lens — 

 the growth and behavior of cells and tis- 

 sues within the living mammal. The 

 stimulus for this study came from the 

 desire to extend to the mammal the type 

 of prolonged microscopic studies of cells 

 and tissues within the living animal that 

 had been carried out in the tails of 

 living amphibian larvae (cf. E. R. 

 Clark, Anat. Rec, 1909, 3, 183; Am. J. 

 Anat., 1912, 13, 351, and 1918, 23, 37). 

 The first chambers were developed by 

 Sandison, J. C. (Anat. Rec, 1924, 28, 

 281; Am. J. Anat., 1928, 41, 447), at the 

 instigation of E. R. Clark. His original 

 attempts were with mica chaml)ers, 

 but his successful ones were constructed 

 of celluloid (cellulose nitrate). The 

 latter provided beautiful preparations, 



in which details of growth and behavior 

 of blood vessels and of other tissues 

 could be seen with highest microscopic 

 magnifications. They remained in the 

 ear a maximum of 4| months. 



After Sandison transferred from 

 Anatomy to Surgery (1928) a group at 

 the University of Pennsylvania under- 

 took to develop, improve and modify 

 the chamber, and succeeded in develop- 

 ing several types of chambers designed 

 for attacking a variety of problems. 



One of the most useful types, which 

 is a modification of Sandison's chamber, 

 is a type named the "round-table" 

 chamber (E. R. Clark, Kirby-Smith, 

 Rex, and R. G. Williams, Anat. Rec, 

 1930, 47, 187). The "round-table" 

 chamber, as described in 1930, has been 

 modified as follows: the washers, both 

 celluloid and rubber, have been found 

 unnecessary in "round-table" cham- 

 bers, though essential in "preformed- 

 tissue" chambers, and in "round-table" 

 chambers installed in dogs' ears; the 

 transplant hole in the base of "round- 

 table" chambers has been omitted, 

 since the Williams removable-top cham- 

 ber has proven a more satisfactory 

 transplant type; the protective discs 

 have been replaced by splints and 

 shields unattached to the chamber; 

 the celluloid rings of both base and top 

 have been stiffened by gluing on an 

 extra 0.66 mm. thick celluloid, over 

 their medial two-thirds; the edges of 

 the table have been bevelled outward, 

 from above down. This type is es- 

 pecially useful for observation of the 

 growth and behavior of blood vessels, 

 lymphatic vessels, connective tissue, 

 nerves, bone, cartilage, epidermis and 

 blood cells. To date it has been the 

 most used and most imitated of all 

 the chamber types. Published results 

 have appeared largely in the Anatomi- 

 cal Record and the American Journal 

 of Anatomy, from 1930 to the present. 

 In nearly all of them, Eleanor Linton 

 Clark has been joint author. 



Construction, installation and meth- 

 ods of study are briefly as follows. 

 The chamber consists of two parts, a 

 base and a top. The base is made of 

 celluloid, 1.8 mm. thick, 3.2 cm. in 

 diameter, at the center of which is a 

 raised round table, 1.3 mm. high, 6.3 

 mm. in diameter. The top consists of 

 a celluloid ring, also 1.8 mm. thick and 

 3.2 cm. in diameter, having a central 

 hole 1.4 cm. across. To the ring is 

 glued a mica disc, 75 micra thick using 

 Varian's glue: gum copal, Venice tur- 

 pentine and xylol (Science, 1931, 73, 

 678). Three holes are bored at points 

 equidistant from each other, near the 



