CHAPTER XXIII. 247 



A mixture of equal parts of nitric acid, glycerin, and water is 

 recommended by MARCACCI (Arch. Ital. BioL, iv, 1883, p. 293) for 

 smooth muscle. 



529. Nitric Acid and Chlorate of Potash (KUHNE, Ueber die peri- 

 pherischen Endorgane, etc., 1862 ; RANVIER, Traite, p. 79).- 

 Chlorate of potash is mixed, in a watch-glass, with four times its 

 volume of nitric acid. A piece of muscle is buried in the mixture 

 for half an hour, and then agitated with water in a test-tube, by 

 which means it entirely breaks up into isolated fibres. 



530. Nitric and Acetic Acid (APATHY, Zeit. wiss. Mik., x, 1898, p. 49). 

 3 volumes glacial acetic acid, 3 of nitric acid, and 20 each of water, 

 glycerin, and absolute alcohol. Macerate leeches for twenty-four hours, 

 and bring them into 70 per cent, alcohol, in which they swell ; then 

 after twenty-four hours, 50 per cent, glycerin, changed till the acid is 

 removed. 



531. Hydrochloric Acid. KONIGSTEIN (Sitzb. Akad. Wien, Ixxi, 1875) 

 takes (for gold-impregnated corneae) equal parts of the concentrated 

 acid, glycerin, and water ; FREUD (ibid., Ixxviii, 1879, p. 102, for nerve- 

 impregnations), 10 parts of acid, 7 of water, 3 of glycerin ; and SCHUBERG 

 and SCHRODER (Zeit. wiss. Zool., Ixxvi, 1904, p. 516) take (for fresh 

 muscles of Hirudinea) hydrochloric acid of 5 per cent. 



532. BELA HALLER'S Mixture (Morphol. Jahrb., xi, p. 321). One 

 part glacial acetic acid, 1 part glycerin, 2 parts water. For the 

 central nervous system of Mollusca a maceration of thirty to forty 

 minutes may be sufficient. 



533. Sulphuric Acid (RANVIER, Traite, p. 78). Macerate for 

 twenty-four hours in 30 grms. of water, to which are added 4 to 5 

 drops of concentrated sulphuric acid. Agitate. For nasal mucosa, 

 crystalline, retina, etc. 



ODENIUS found very dilute sulphuric acid to be the best reagent 

 for the study of nerve endings in tactile hairs. He macerated hair- 

 follicles for from eight to fourteen days in a solution of from 3 to 

 4 grs. of " English sulphuric acid " to the ounce of water. 



Hot concentrated sulphuric acid serves to dissociate horny 

 epidermic structures (horn, hair, nails). 



534. Oxalic Acid. Maceration for many days in concentrated 

 solution of oxalic acid has been found useful in the study of nerve- 

 endings. 



535. SCHIEFFERDECKER'S Methyl Mixture (for the retina) (Arch, 

 mik. Anat., xxviii, 1886, p. 305). Ten parts of glycerin, 1 part of 



