MACERATION AND DIGESTION. 317 



Eecommended especially for epithelia and muscle. A few 

 hours' maceration is generally sufficient. 



538. Osmic and Acetic Acid (the HERTWIGS, Da* Nerven- 

 system u. die Sinnesorgane der Medusen, Leipzig, 1878, and 

 Jen. Zeitschr., xiii, 1879, p. 457 ; Journ. Roy. Mic. Soc., iii, 

 1880, p. 441, and [N. S.] iii, 1883, p. 732). 



0'05 per cent, osmic acid . . 1 part. 



0*2 acetic acid . . 1 

 Medusae are to be treated with this mixture for two or 

 three minutes, according to size, and then washed in repeated 

 changes of O'l per cent, acetic acid until all traces of free 

 osmic acid are removed; they then remain for a day in 0*1 

 per cent, acetic acid, are washed in water, stained in BE ALE'S 

 carmine, and preserved in glycerin. 



For Actiniae the osmic acid is taken weaker, 0'04 per cent. ; 

 both the solutions are made with sea water ; and the washing 

 out is done with 0'2 per cent, acetic acid. If the maceration 

 is complete, stain with picro-carmine ; if not, with BEALE'S 

 carmine. 



539. BELA HALLER'S Mixture (MorphoJ. Jahrb., xi, p 321). 

 One part glacial acetic acid, 1 part glycerin, 2 parts water. 

 Specially recommended for the central nervous system of 

 Mollusca (Ehipidoglossa) . A maceration of thirty to forty 

 minutes may be sufficient, the cells showing less shrinkage 

 than with other liquids. 



540. Nitric Acid. Most useful for the maceration of muscle. 

 The strength used is 20 per cent. After twenty-four hours' 

 maceration in this, isolated muscle-fibres may generally be 

 obtained by shaking the tissue with water in a test-tube. 

 Preparations may afterwards be washed with water and put 

 up in strong solution of alum, in which they may be pre- 

 served for a long time (HOPKINS, Proc. Amer. Soc. of Micro- 

 scopists, 1890, p. 165; Zeit. f. iviss. Mik., ix, 1, 1892, p. 86). 



Maceration is greatly aided by heat, and at a temperature 

 of 40 to 50 C. may be sufficiently complete in an hour 

 ((TAGE). 



541. Nitric Acid and Chlorate of Potash (KiJHNE, Ueber die 

 peripherischen Endorgane, etc., 1862; RANVIKR, Traite, 



