ARGON 



21 



ARTERIES 



ing Clorox or other suitable hypochlorite 

 solution and using it as a stock solution. 

 Leave the slide in the hypochlorite 

 solution exactly 60 sec. at room temper- 

 ature, holding it stationary. 



4. Move quickly [without draining) 

 into a solution containing per 100 cc: 

 15 gm. urea, 70 cc. tertiary butyl alcohol 

 and potassium hydroxide to make the 

 concentration of the latter 0.015 N. 

 Move the slide gently in the solution 

 for 10 sec, then transfer to another jar 

 of the same solution for 2 min. 



5. Transfer to 100% tertiary butyl 

 alcohol, moving the slide gently for 

 10 sec, then place in a second jar of the 

 same reagent for 3^ min. 



6. Pass through three changes of 

 xylene for 10 seconds, 1 minute and 

 2 min., respectively. 



7. M.ount with Permount containing 

 aniline. This reagent is prepared by 

 dissolving 0.1 cc. of aniline in 100 cc. 

 of xylene. One volume of this solution 

 is mixed with four volumes of Permount. 



Reagents 2, 3 and 4 must be made 

 fresh daily. It is best not to let any 

 water accumulate in the tertiary butyl 

 alcohol. 



The three arginine methods are all 

 based on the Sakaguchi reaction, which, 

 in biological materials, is specific for 

 arginine, galegine and agmatine. The 

 latter two are extremely rarely en- 

 countered and so for most purposes, it 

 is specific for arginine. The histo- 

 chemical methods are specific for pro- 

 tein-bound arginine, since free arginine 

 is inevitably removed by the pro- 

 cedures. 



Argon, see Atomic Weights. 



Argyrophilic Fibers. Because of their affin- 

 ity for silver, Reticular Fibers are often 

 called argyrophilic. 



Arneth Count of lobes of granular leucocytes 

 as a basis for estimation of their rela- 

 tive age. See Leucocyte Counts. 



Arsenic 1. Use 10% neutral formalin in aq. 

 dest. after test with hydrogen sulphide 

 shows absence of trace of metals. To 

 100 cc. add 2.5 gm. copper sulphate. 

 Fix small pieces of tissue 5 days. Wash 

 24 hrs. in running water. Imbed in 

 paraffin. Direct examination of section 

 after removal of paraffin shows arsenic 

 as well defined green granules of hydro- 

 arsenite of copper (Scheele's green). 

 If neutral acetate of copper is employed 

 in place of the sulphate the green 

 granules are of acetoarsenite of copper 

 (Schweinf urth's green ) . 



2. Fix pieces of tissue 12-24 hrs. in 

 abs. ale 50 cc. ; chloroform, 50 cc. ; pure 

 hydrochloric acid, 3 cc. saturatea by 

 passage of pure hydrogen sulphide. In 

 sections the arsenic ppt. appears as yel- 



low granules. Double coloration with 

 hematein-eosin is possible. Both tech- 

 niques have been devised by Castel 

 (P., Bull. d'Hist. Appl., 1936, 13, 106- 

 112). He lias described the histologic 

 distribution of the arsenic. See, how- 

 ever, paper by Tannenholz , H . and Muir, 

 K. B., Arch. Path., 1933, 15, 789-795 who 

 employed a somewhat similar method 

 ana were unable to conclude that the 

 yellow crystals were in fact those of 

 arsenic trisulphide. They considered 

 them more probably a sulphur-protein 

 combination. 



Consult the detailed account of Os- 

 borne's method for arsenic given by 

 Heuper, W. C, Occupational Tumors 

 and Allied Diseases. Springfield: 

 Thomas, 1942, 896 pp. (p. 50). This 

 releates particularly to localization of 

 arsenic in the skin. 



The distribution to the several tissues 

 of radioactive arsenic injected intra- 

 venously into rabbits as sodium arsenate 

 has been investigated by duPont, O., 

 Irving, A. and Warren, S. L., Am. J. 

 Syph. etc., 1942, 26, 96-118. It is impor- 

 tant to determine whether the results 

 conform with those given by the micro- 

 chemical techniques. 



Arsphenamines. The specificity of the 

 silver reaction of Jancs6, N., Ztschr. 

 f. d. Ges. exper. Med., 1929, 65, 98 is 

 questioned by Gomori, G., J. Mt. 

 Sinai Hosp., 1944-45, 11, 317-326 since 

 it may demonstrate other reducing sub- 

 stances beside the arsphenamines. 



Artefacts, see Artifacts. 



Arteries. If one wishes an elastic artery 

 take a large trunk near the heart such as 

 the aorta, innominate or subclavian; if, 

 on the other hand, a typical muscular 

 artery is required select one further 

 afield like the radial or external carotid. 

 Arterial walls are seldom examined 

 microscopically in vivo because they are 

 relatively large and difficult to get at 

 without injury. An exception in man is 

 the retinal artery which can be seen 

 by ophthalmoscopic examination. To 

 closely observe excised pieces of arteries 

 is all too frequently neglected. The 

 tissue elements are so tightly bound to- 

 gether that to tease them apart for study 

 at high magnification is rather unsatis- 

 factory. However, when the adventitial 

 adipose and connective tissue is stripped 

 off from a fresh specimen, the remainder 

 of the wall can very advantageously be 

 made translucent by treatment with 



Eure glycerin for 1-2 hrs. as described 

 y Winternitz, M. C, Thomas, R. M. 

 and LeCompte, P. M. in their book "The 

 Biology of Arteriosclerosis", Spring- 

 field: Thomas, 1938, 142 pp. Since the 

 color of the blood is preserved within 



