2/8 HISTOLOGY 



then steeped in water containing 3 per cent each of nitric and hydro- 

 chloric acid. Other mixtures may be used, as chloroform containing 

 a drop or two of strong nitric acid. Or 50 per cent alcohol warmed 

 and saturated with picric acid will depigment. Alcohol, glycerin, and 



FIG. 244. Well-developed chromatophore of the same cephalopod. Processes completed and 

 extensive connection with a nerve plexus. Nucleus in base of each process, pg.s., pigment 

 . sac containing pigment granules and one nucleus. (After C. CHUN.) 



water in equal parts, through which chlorine gas is passing, is also a 

 good reagent. 



The fixation will itself often remove the pigment. This is not to 

 be recommended, as it is usually associated with a poor fixation. Well- 

 fixed tissues nearly always show the pigment in good condition. 



LITERATURE 



CHUN, C. " Uber die Natur und die Entwicklung der Chromatophorcn bei den Cepha- 



lopoden," Verh. der Deut. Zool. Gesell. Mai, 1902, Leipzig. 

 CARLTON, F. C. "The Color Changes in the Skin of the Florida Chameleon, Anolis caro- 



linensis," Proc. Am. Ac. of Arts and Sciences, Vol. 39, Nr. 10. 

 FLEMMING, W. "Uber die Theilung von Pigmentzellen u. s. w." in Arch. f. mik. Anat., 



Band 35. 



KEPNER, W. A. "Notes on the Genus Leptophrys" Am. Nat., Vol. 40, 1906. 

 VON LINDEN, M. G. "Red and Yellow Pigment of Vanessa," J. R. Mic. Soc., 1904, 



Nr. i. 

 VERWORN, MAX. "General Physiology," p. 109. 



