252 DECALCIFICATION 



course of twelve to twenty-four hours ; running water, forty-eight 

 hours ; alcohol. 



594. Nitric Acid and Alcohol. Three per cent, of nitric acid in 

 70 per cent, alcohol. Mayer has long used 5 per cent, acid in 90 per 

 cent, alcohol. Soak specimens for several days or weeks. Pure nitric 

 acid, even if weak, readily exercises a gelatinising action on bone ; 

 whilst the addition of alcohol (or of alum) counteracts this action (Fish, 

 Ref. Handb. Med. Sci., Supp., p. 425). 



Thoma (Zeit. zoiss. Mik., viii, 2, 1891, p. 191) takes 5 volumes of 

 95 per cent, alcohol and 1 volume pure concentrated nitric acid. Leave 

 bones in this mixture, changing the liquid every two or three days, 

 until thoroughly decalcified, which should happen, even with large 

 bones, in two or three weeks. Wash out until every trace of acid is 

 removed (i.e., for some days after no acid reaction is obtained with 

 litmus paper) in 95 per cent, alcohol containing an excess of precipitated 

 carbonate of lime. This may take eight to fourteen days, after which 

 the tissues will stain well and may be treated as desired. 



595. Nitric Acid and Formol. Schridde (Hcematol. Tecfm., Jena, 

 1910, p. 21) decalcifies material fixed in formol or formol-Miiller in a 

 mixture of 1 part of formol, 1 of nitric acid, and 9 of water. 



596. Nitric Acid and Alum (Gage, quoted from Fish, § 594). A 

 saturated aqueous solution of alum is diluted with an equal volume of 

 water, and to each 100 c.c. of the dilute solution is added 5 c.c. of strong 

 nitric acid. Change every two or three days, until the decalcification 

 is complete. For teeth this is said to be, perhaps, a better decalcifier 

 than the alcohol mixture. 



597. Sulphurous Acid (Ziegler, Festschr. f. Kupffer, 1889, 

 p. 51), A saturated solution in water. Wash out for twenty- 

 four hours. Acts rapidly and preserves well. Best used after 

 fixation with formol. 



598. Hydrochloric Acid (see § 590). Ranvier says that it may be 

 taken of 50 per cent, strength, and then has a very rapid action. To 

 counteract the swelling action of the acid, sodium chloride may be added 

 (voN Ebner), see Haug's paper quoted § 590. He takes either 100 c.c. 

 cold saturated solution of sodium chloride in water, 100 c.c. water, and 

 4 c.c. hydrochloric acid. Preparations to be placed in this, and 1 to 2 c.c._ 

 hydrochloric acid added daily until they are soft. Or, 2-5 c.c. of 

 hydrochloric acid, 500 of alcohol, 100 of water, and 2-5 gm, of sodium 

 chloride. Haug prefers the proportions of 10 to 50 of acid, 70 of 

 alcohol, 30 of water, and 0-5 of salt. 



599. Hydrochloric Acid and Chromic Acid (Bayerl, Arch. mik. Anat., 

 1885, p. 35). Equal parts of 3 per cent, chromic acid and 1 per cent, 

 hydrochloric acid. For ossifying cartilage. Haug recommends equal 

 parts of 1 per cent, hydrochloric acid and 1 per cent, chromic acid 

 (Inc. cif.). 



600. Hydrochloric Acid and Glycerin. Glycerin, 95 ; hydrochloric 

 acid, 5 (Squire's Methods and Formidce, p. 12), 



601. Trichloracetic Acid. Partsch (verh. Ges. D. Naturf. 

 Aertze, 1895, 2 Theil, 2 Halfte, p. 26) uses a 5 per cent, aqueous 

 solution, and Neuberger {Centralh. Phijs., xi, 1897, p. 494) a 

 4 per cent. one. Action energetic, preservation said to be excellent. 



602. Picrid Acid should be taken saturated and changed frequently. 

 Its action is weak, but it gives good results with small objects. 



Picro-nitric or Picro-hydrochloric Acid. Action very rapid. 



