SILVER DEPOSITS 



315 



SILVER LINEATION 



about 60 cm. above cannula. When 

 clear fluid, free from blood, appears in 

 inferior vena cava, clamp tube and 

 replace citrate solution with silver 

 solution. Raise bottle about 150 cm. 

 above cannula and release clamp. De- 

 termine length of time of perfusion by 

 trials. When complete, immediately 

 make frozen sections to determine re- 

 sults and fix other pieces in 10% 

 formalin for 24 hrs. Cut paraffin sec- 

 tions desired thickness. Mount them 

 in usual way, run down to water and 

 develop in light in diluted photographic 

 developer or simply by direct exposure 

 to sunlight or arc light. Counterstain 

 in Mayer's Acid Carmine, hematoxylin, 

 acridine red or some other suitable dye. 

 Dehydrate, clear, mount in balsam. 



Silver Deposits, methods for removal, 

 Lillie, p. 135. 



Silver Diaminohydroxide after Sensitizing 

 with Sodium Sulfite for Neuroglia — 

 Written by William M. Shanklin, 

 American University of Beirut, Beirut, 

 Lebanon. March 30, 1951 — Fix small 

 fresh pieces of the central nervous sys- 

 tem in formalin ammonium bromide for 

 4 days at room temperature (Del Rio 

 Hortega, P., Arch. Hist. Normal Y 

 Path., 1942, 1, 165-205, 329-361; 1943, 

 2, 231-244, 577-604) : Formalin (Merck, 

 blue label 40%) 70 ml.. Ammonium 

 bromide 14 gm. and aq. dest. 680 cc. 

 Wash 10 hrs. in aq. dest. to which 30 

 drops of strong ammonia water are 

 added for each 100 cc. of water, and 

 cover the jar. Wash in two changes of 

 aq. dest. for 1-2 hrs. in each; dehydrate 

 with alcohol. Clear in cedar oil fol- 

 lowed by xylene 30 min. Infiltrate 

 with paraffin for 3-4 hrs., embed, sec- 

 tion at 10-15 M and fix to slide by the 

 albumen water method. Remove the 

 paraffin with xylene, dehydrate with 

 alcohol and pass through three changes 

 of aq. dest. 1-2 min. each. Sensitize 

 by placing the slides in 5% aq. sodium 

 sulfite, 2 hrs. Pass quickly through 3 

 changes of aq. dest. To prepare silver 

 diaminohj^droxide solution place 1 

 ml. 28% ammonia water in a small 

 flask and add 7 or 8 ml. 10% silver 

 nitrate rapidly. Continue to add 10% 

 silver nitrate drop by drop shaking 

 between each addition to clear the 

 solution until a faint permanent turbid- 

 ity remains after the last drop is added. 

 This takes a total of 9 to 10 ml. silver 

 solution. Then dilute the resultant 

 solution with an equal volume of aq. 

 dest. (Lillie, R. D., Stain Techn., 1946, 

 21, 69-72; Histopathologic Technic, 

 Philadelphia: Blakiston Co. 1948). 

 Impregnate by immersion in the silver 

 solution at room temperature for 2 to 5 



min.; the time is varied until the opti- 

 rnum is determined. The silver solu- 

 tion will keep for several daj'^s but 

 should be changed frequently after 

 use. Dip in aq. dest. 1 or 2 sec. Re- 

 duce for 1 min. in 2% neutral formalin 

 (Merck, blue label) agitating gently. 

 The formalin should be changed fre- 

 quently. Wash in aq. dest. for 1 min. 

 Tone in yellow gold chloride (1 g. to 

 500 ml. aq. dest.) a few seconds to one 

 minute. This step must not be pro- 

 longed beyond the exact time needed. 

 Fix in 5% hypo for 1-2 min. Wash in 

 tapwater and counterstain lightly with 

 1% picric acid. Dehydrate in alcohol, 

 clear in xylene, mount in neutral bal- 

 sam and cover with cover slips. 



This method successfully stains 

 fibrous and protoplasmic astrocytes, 

 microglia and oligodendroglia. By em- 

 bedding the tissue in paraffin the prob- 

 lem of overformalinization is avoided 

 and the tissues are still suitable for 

 staining years later (See Nassar, T. K. 

 and Shanklin, W. M., Stain Techn., 

 1951,26, 13-18). 

 Silver Electrode of Linderstrom-Lang, 

 Palmer and Holter described by Glick, 

 p. 183. 

 Silver Gray, see Nigrosin, water soluble 

 Silver Lineation on pulmonary alveolar 

 walls — Written by C. C. Macklin, Dept. 

 of Histological Research, The Univer- 

 sity of Western Ontario, London, Can- 

 ada. November 28, 1951 — The following 

 modernization of a very old tech- 

 nique is recommended. Immediately 

 after cessation of the circulation the 

 collapsed lungs of healthy mammals are 

 filled, via the trachea or a large bron- 

 chus, with 0.2 per cent aqueous silver 

 nitrate for not more than one minute; 

 they are at once drained. They are 

 promptly refilled with distilled water 

 and evacuated, and this last process is 

 repeated. They are then filled with 

 10% neutral formalin in water; the 

 trachea is tied and the preparation im- 

 mersed in the same fixative for 24 hours 

 or more. The degree of distention 

 should be approximately that of full 

 inspiration (See C. C. Macklin, J. Thor. 

 Surg., 1938, 7, 536-551, for further 

 details and bibliographj')- Silver cit- 

 rate may be used instead of silver 

 nitrate (see R. D. Bensley, Am. J. 

 Anat., 1929, 40, 146-169). Blocks are 

 cut out and sectioned while frozen, or 

 after having been embedded in paraffin 

 or celloidin. Flattened frozen sections 

 are best for en face examination of the 

 silver lines on an expanse of alveolar 

 wall. The silver lines are darkened by 

 exposure of the sections to direct sun- 

 light; or, as an alternative, the lungs 



