PHLOKOGLUOIN. 293 



THOMA (Zeit.f. wiss. Milt., viii, 2, 1891, p. 191) gives the 

 following method. Take 5 vols. of 95 per cent, alcohol and 1 

 vol. pure concentrated nitric acid. Leave bones in this mix- 

 ture, 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 chalk. This may take eight to four- 

 teen days, after which the tissues will stain well and may be 

 treated as desired. 



562. Phloroglucin (ANDEER, Centralbl. f. d. med. Wiss., xii, 

 xxxiii, pp. 193, 579 ; Intern. Monatschr., i, p. 350 ; Zeit.f. wiss. 

 Mik., 1885, pp. 375, 539; Journ. Roy. Hie. Soc., 1887, p. 504; 

 HAUG, Zeit.f. wiss. Mik., viii, 1, 1891, p. 8; FEEREBI, ibid., ix > 

 2, 1892, p. 236; Bull. R. Accad. Med. di Roma, 1892, p. 67). 

 This is the most recent of the decalcification methods. It has 

 the advantages of being the most rapid of any, and of pre- 

 serving the tissues very well (with the exception of blood). 



Phloroglucin by itself is not a solvent of lime salts ; its 

 function in the mixtures given below is so to protect the 

 organic elements of tissues against the action of the mineral 

 acids that these can be used in a much more concentrated 

 form than would otherwise be advisable. 



HAUG advises the following procedure : Bring 1 grm. of 

 phloroglucin into 10 c.c. of pure, not fuming nitric acid 

 (1*4 sp. gr.), and warm very slowly and carefully with gentle 

 agitation. There is formed a clear solution of (presumably) 

 a nitrate of phloroglucin. Dilute the solution with 100 c.c. 

 of distilled water, and add 10 c.c. of nitric acid. This gives 

 a solution containing 20 per cent, of acid, which is the proper 

 proportion. More water may be added to the solution, to 

 make it up to 300 c.c., if nitric acid be also added in the 

 proportion given. But the dilution must not be carried 

 beyond this point, in order that the preservative action of 

 the phloroglucin be not overmuch weakened. The process of 

 decalcification in this solution is extremely rapid, and there- 

 fore should be carefully watched. Foetal and young bones 

 become quite soft in half an hour; small pieces of old and 

 hard bones (femur, temporal bone) in a few hours. Teeth 



