CHAPTER XXIV. 253 



be well fixed and imbedded in celloidin ( 546) ; harden in alcohol ; 

 remove the alcohol with water ; put for twelve to twenty-four hours 

 (large specimens longer) into, nitric acid of 3 to 5 per cent., then into 

 a 5 per cent, solution of sulphate of lithium or sodium, to be changed 

 once in the course of twelve to twenty-four hours ; running water, 

 forty-eight hours ; alcohol . 



550. 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. Sri., Supp., p. 425). 



THOMA (Zeit. wiss. 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 tra.ce 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. 



551. Nitric Acid and Formol. SCHRIDDE (Hcematol. Techn., 

 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. 



552. Nitric Acid and Alum (GAGE, quoted from FISH, 550}. 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. 



553. Sulphurous Acid (ZIEGLER, Festschr.f. Kupffer, 1899, p. 51). 

 A saturated solution in water. Wash out for twenty-four hours. 

 Acts rapidly and preserves well. Best used after fixation with 

 formol. 



554. Hydrochloric Acid (see 547). 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 547. He takes either 100 c.c. 



