CAPILLARIES 



56 



CAPRI BLUE 



lated. When the break is made across 

 the tube, at right angles, the rim on one 

 side can be ground down on a water stone 

 so as to produce a similarly projecting 

 lip. In either case it is necessary to 

 remove sharp cutting edges from both 

 ends of the cannula by smoothing in a 

 flame. The 6 mm. wide body of the 

 cannula should be 3-4 cm. long for con- 

 venient attachment of rubber tube. 

 Obviously larger cannulas are required 

 for larger vessels. Those for Micro- 

 injection are very much smaller, made 

 of hard glass and do not require to be 

 tied in. 

 Capillaries. In living humans these can 

 best be seen in the skin by the method 

 of Capillaroscopy. Render the epider- 

 mis at the root of the finger nail trans- 

 lucent by addition of a drop of highly 

 refractive oil and examine directly at 

 fairly high magnification the capillary 

 loops in the dermal papillae. It is 

 possible to record their changes by 

 making moving pictures through a long 

 period of time. See review by Wright, 

 I. S. and Druryee, A. W., Arch. Int. 

 Med., 1933, 52, 545-575. See also 

 Gingiva. 



In living mammals the most favorable 

 site in which to watch capillaries at high 

 magnification is in the transparent 

 chambers of the Sandison's Technique. 

 For shorter periods they can be studied 

 in the displaced but living pancreas by 

 the methods of Covell, W. P., Anat. 

 Rec, 1928, 40, 213-223 and O'Leary, J. 

 L., ibid, 1930, 45, 27-58. Some changes 

 in Permeability of living capillaries are 

 evidenced by the trypan blue capillary 

 permeability test. If microdissection 

 is intended and a shift to the tongues 

 and nictitating membranes of frogs is 

 made consult Zweifach, B. W., Anat. 

 Rec, 1934, 59, 83-108, and Am. J. Anat., 

 1937, 60, 473-514. The results have 

 been recorded in moving pictures. 

 Supravital staining of the tissues just 

 mentioned with janus green (Bensley, 

 R. R., and Vimtrup, B., Anat. Rec, 

 1928, 39, 37-55) affords beautifully clear 

 views of the muscular elements of 

 arterioles grading into capillaries. See 

 Perivascular Cells, Rouget Cells. 



For investigations on the topographic 

 arrangement of capillaries arterial injec- 

 tions with Carmine, Berlin Blue or 

 some other easily recognizable material 

 followed by clearing by the Spalteholz 

 method may be helpful. When however 

 any fluid is injected, under great pres- 

 sure, into a fresh, relaxed tissue that can 

 easily swell there is a chance that an 

 exaggerated idea of the capillaries will 

 be conveyed. In resting muscle for 



instance a large proportion of the 

 capillaries are collapsed (Krogh). 



The structure of the endothelial 

 capillary wall is relatively uncompli- 

 cated. The outlines of the endothelial 

 cells are nicely revealed in pink by the 

 Silver Chloride Dichlorfluorescineate 

 technique or in black by simply treating 

 with silver nitrate. Nuclear and cyto- 

 plasmic structure can be brought out by 

 methods used for other tissues. Nerve 

 fibers closely accompany most capil- 

 laries. The existence of actual nerve 

 endings on the wall is debated. The 

 most convincing looking preparations 

 of human tissues have been secured by 

 Stohr, Ph., Zeit. f . Zellf . u. Mikr. Anat., 

 1926, 3, 431-448 who employed a modifi- 

 cation by Gros of the Bielchowsky 

 silver technique (see particularly his 

 Fig. 2). See Sinusoids. 

 Capillaries of brain. Lepehne-Pickworth 



Eeroxidase method simplified by Camp- 

 ell and Alexander (Mallory, p. 257). 

 Fix for 1-3 weeks in 10% formalin. To 

 make required solution dissolve 0.1 gm. 

 benzidine in 0.5 cc glacial acetic acid 

 and add 20 cc. aq. dest. Dissolve 0.1 

 gm. sodium nitroprusside in 10 cc. aq. 

 dest. and add benzidine solution. Add 

 aq. dest. to 100 cc. In case a ppt. forms 

 filter it out. Solution must be fresh. 

 Cut frozen sections 200-300/:( and wash 

 in aq. dest. H hr. Change to above 

 described solution for 5 hr. at 37 °C. 

 agitating often. Wash in aq. dest. 10 

 sec. and transfer to 100 cc. aq. dest. + 

 2-3 drops 30% hydrogen peroxide for 

 i hr. at 37°C. shaking frequently. 

 Wash in aq. dest. and dehydrate in 70%, 

 95% and absolute alcohol. Clear in 

 xylol and mount in balsam. Blood ves- 

 sels black in almost colorless back- 

 ground. This method has the advantage 

 of not involving vascular perfusion. 

 See comparison of injection and red cell 

 staining methods for quantitative study 

 of capillaries of central nervous system 

 (Drummond, S.P., Anat. Rec, 1944, 89, 

 93-106). Microinjection of capillaries, 

 Chambers, R. W. and Kopac, M. J., 

 McClung's Microscopical Technique, 

 1950, p. 530. 



Capillary Fragility Tests. Discussion (Gold- 

 man, L. and Corrill, E. M., J. Invest. 

 Dermat., 1945,6, 129-147). 



Capillary Respirometry. The development 

 of the techniques is described bv Tobias, 

 J. M., Physiol. Rev., 1943, 23, 51-75. 

 A differential respirometer is described 

 by Cunningham, B. and Kirk, P. L., 

 J. Gen. Physiol., 1940, 24, 135-149. 

 Whole problem is discussed by Glick, 

 pp. 314-326. 



Capri Blue (CI, 876), a basic dye of light 



