VITAL STAINING 345 



With litmus the vacuoles of macrophages stain red, thus indicating 

 their acid character. Nassonow {Zeit. f. Zellforsch., xi, ]930, 

 p. 177 ; Protoplasma, xv, 1932, p. 23!>) has devised a technique 

 for studying intracellular jjH using neutral red and other basic 

 dyes. Chambers {Proc. Soc. Expt. Biol. Med., xxvii, 1930, p. 809) 

 found that methyl red vitally stained cells when the pH of the 

 surrounding medium was deiinitcly below 6-0. For investigating 

 intracellular hydrogen ion concentration the micro-injection 

 technique is particularly useful. For references to papers by 

 Chambers and his collaborators, see Chambers and Ludford 

 (Proc. R. S. B., ex, 1932, p. 120). 



775. Vital Staining as a Method for Investigating the Mechanism 

 of Mitosis. Aberrations of mitosis are brought about by vital 

 staining. According to von Mollendorff {Zeit. f. Zellforsch., 

 xxiii, 1936, p. 746) neutral red in a concentration of 1 in 200,000 

 interferes with mitosis in tissue cultures. Politzer {Biochem. 

 Zeit., cli, 1924, p. 43) found that a concentration of 1 in 150,000 

 resulted in a decrease in the number of mitoses in ejoidermal cells 

 of salamander larvae after two hours, and there were many 

 " pseudo-amitoses." Nile blue had a similar action. Auramine 

 and brilliant cresyl blue arrested mitosis at metaphase. Ludford 

 (Arch.f. expt. Zellforsch., xviii, 1936, p. 411) found that auramine 

 had a similar action in vitro, preventing the formation of the 

 mitotic spindle. 



Vital staining with methylen blue affords a means of demon- 

 strating cells in division in tissue cultures, since dividing cells do 

 not stain so intensely as " resting " cells (Ludford, Arch.f. expt. 

 Zellforsch., xvii, 1935, p. 339). 



PART V. LITERATURE 



776. General Reviews 



VON Mollendorff, W., Ergeb. Physiol., xviii, 1920, p. 141. Cappell, 

 D. F., J. Path. Bad., xxxii, 1929, p. 595. Gicklhorn, J., Ergeb. Bio., 

 vii, 1931, p. 549. Nagel, A., Oppenheimer' s Hdb. Bioch. d. Mensch. 

 u. d. Tiere, i, 1933, p. 783. 



777. Vital Staining for Specialised Researches 

 Protozoology 



Vonwiller, p., AbderhalderC s Hdbuch. d. biol. Arbeitsmeth., Abt. V 

 Tail. 2, 1921, p. 87. 



Embryology 

 WiNTREBERT, P., BulL Assoc. d. Atiat., xxvii, Reunion Report, 1932. 



Cellular Physiology and Pathology 

 Ludford, R. J., Biol. Rev., viii, 1933, p. 357, 



Cancer Research 



Ludford, R. J., Proc. R. S. B., civ, 1929, p. 493 ; lOth Sci. Rep. 

 Imp. Cancer Res. Fd., 1932, p. 1 ; ll//j ibid., 1934, p. 147. 



