ARTICULAR NERVE TERMINALS 



23 



ATABRINE 



within the body. When after Vital 

 Staining or Supravital Staining still 

 living cells are examined in approxi- 

 mately isotonic media, there is a grave 

 danger of artifact if the study is pro- 

 longed because the cells are slowly dying. 

 3. In fixed tissues the degree of di- 

 vergence from the normal living condi- 

 tion is obviously much greater than in 

 the case of still living ones. However 

 death has been sudden so that artifacts 

 due to gradual death are eliminated. If 

 the technique has been carefully stand- 

 ardized the same fixative applied to the 

 same type of cell in the same physiologi- 

 cal state is likely to yield similar results. 

 Among common artifacts are: 1. The 

 shrinkage and increased affinity of cells 

 near the surface for stains due to allow- 

 ing the surface of the tissue to dry be- 

 fore fixation. 2. The glassy appearance 

 of nuclei and cytoplasm sometimes oc- 

 casioned by overheating in imbedding 

 or in spreading out sections. 3. Mate- 

 rial within blood vessels faintly resem- 

 bling organisms caused by coagulation 

 of blood proteins. 4. Extraneous sub- 

 stances either present in the albumen 

 fixative used to mount the sections or 

 deposited as dust from the air. Careful 

 focussing is required. See Agonal and 

 Postmortem changes, Ice Crystal Arti- 

 facts. A paper by Bensley, R. R., Exp. 

 Cell Res., 1951, 2, 1-9 on "Facts versus 

 Artifacts in Cytology: the Golgi ap- 

 paratus" is illuminating. See Agonal 

 and Postmortem changes. Ice Crystal 

 Artifacts, Normality, Nucroscopic. 

 Articular Nerve Terminals. — Written by 

 Dr. E. D. Gardner, Wayne University 

 School of Medicine, Detroit. June 15, 

 1950— Gardner, E. D., Anat. Rec, 

 1942, 83, 401-419, adapted silver 

 methods to the demonstration of nerve 

 terminals in the knee joints of mice 

 1-60 days old. Subsequently, J. Comp. 

 Neur., 1944, 80, 11-32, similar methods 

 were applied to the knee joints of 33- 

 and 46-day-old cat fetuses. The Bodian 

 method was used, but the necessary 

 protargol seems no longer to be avail- 

 able. It appears, however, that similar 

 results can be obtained with Romanes' 

 staining method (J. Anat., 1950, 84, 

 104-115) . A variety of fixatives are satis- 

 factory, particularly Bouin and acetic- 

 formol-alcohol. Decalcify in 20% 

 sodium citrate and 50% formic acid, 

 equal volumes, prior to embedding. 

 Sections are placed overnight at 56 °C. 

 in the following solution: Distilled 

 water 50 ml., 0.1% silver nitrate 2.9 

 ml., and 0.1% sodium chloride 1.0 ml. 

 To this are added a few drops of very 

 weak ammonia sufficient just to turn 

 phenol red paper pale pink. Subsequent 



treatment is similar to that of the 

 Bodian method. Silver methods are 

 excellent for following nerves in thin, 

 serial sections, for tracing nonmyeli- 

 nated fibers and for small nerve end- 

 ings. But large, proprioceptive endings 

 such as occur in the posterior region of 

 the knee joint capsule are best demon- 

 strated by methylene blue. Excellent 

 results may be obtained by using 0.05% 

 methylene blue in normal saline. It 

 may be perfused, injected into the 

 joint cavity or pieces of capsule can be 

 removed and placed in methylene blue 

 at 37°C. for 10-15 minutes. They are then 

 exposed to air for 10-15 minutes, placed 

 in 8% ammonium molybdate in normal 

 saline for at least 1-2 hours and then 

 dehydrated rapidly in cold alcohols. 

 Whole mounts are made after clearing 

 in xylol. This method shows better than 

 any other the grouping and distribution 

 of large endings, and the preparations 

 are also satisfactory for small fibers, 

 particularly those in vascular plexuses. 



Artificial Fever, influence on adrenal (Bern- 

 stein, J. G., Am. J. Anat., 1940, 66, 

 177-196). See Cramer, W., Fever, 

 Heat Regulation and the Thyroid- 

 Adrenal Apparatus. London: Long- 

 mans, Green & Co., 1928, 153 pp. 



Asbestos, see Lillie p. 135. 



Ascorbic Acid. Colorimetric method of 

 Lowry, O. H., Lopez, J. A. and Bessey, 

 O. A., J. Biol. Chem., 1945, 160, 609- 

 615 for blood serum in volumes of 10 

 ix\ up. Pijoan, M. and Gerjovich, H. J., 

 Science, 1946, 103, 202-203 advise cau- 

 tion in use with tissues. See titrimetric 

 technique of Click, D., J. Biol. Chem., 

 1935, 109, 433-436. See Vitamin C. 



Ascorbic Acid, see Vitamin C. 



Aspirated Sternal Marrow, method for 

 preparing smears and sections (Gordon, 

 H., J. Lab. & Clin. Med., 1940-41, 26, 

 1784-1788). 



Astra Violet, see Leishmania. 



Astrocytes. These cells make up one of the 

 two divisions into which neuroglia is 

 usually divided. They also pass under 

 the names of "Classical neuroglia" 

 and "macroglia." They are star shaped 

 cells with processes radiating in all 

 directions some of which form peri- 

 vascular expansions on the surface of 

 small blood vessels. The most selective 

 methods for their demonstration usually 

 involve some form of metallic impregna- 

 tion. For details see Chapter by Pen- 

 field and Cone in McClung's Micro- 

 scopical Technique, 1950, p. 407 and 

 Lillie's Histopathologic Technic, 1948, 

 p. 237. In this book see Neuroglia. 



Atabrine, anti-malarial agent; fluorescence 

 microscopical localization of atabrine 



