Organic Substances 79 



chromaffin phenol is not completely abolished even after 24 

 hours' acylation. 



For the reasons mentioned, great caution is warranted in 

 the evaluation of the results of DanielH's technique. Its mech- 

 anism is not entirely clear, and the possibility that the re- 

 sults are largely nonspecific cannot be ruled out. 



2. The sugar moiety is identified by aldehyde reactions 

 after acid hydrolysis. The most commonly used aldehyde re- 

 agent is SchiE's, which will demonstrate only desoxyribose 

 (Feulgen's nucleal reaction ).^^ Schiff's reagent can be re- 

 placed by other chromogenic carbonyl reagents, such as 2- 

 hydroxy-3-naphthoic acid hydrazide followed by azo-coup- 

 ling,^^ with essentially similar results. Turchini's reagent 

 (9-phenyl-2,3,7-trihydroxy-6-fluorone) will condense with 

 both ribose and desoxyribose and, in fact, even with hex- 

 oses.^^ The condensation products with these sugars have 

 different colors (ribose, yellowish pink; desoxyribose, bluish 

 purple; hexoses, reddish purple ) . RNA must be protected by 

 fixation in dichromate-containing mixtures (which make nu- 

 cleic acids more resistant to hydrolysis; Hillary );^^ otherwise 

 it may be lost in the procedure. No reports on the reliability 

 of this method are available so far except by Turchini and 

 his co-workers. 



89. Feulgen, R.: Die Nuclealfarbung. In Abderhalden's Handb. d. biol. 

 Arbeitsmeth., ¥2-2:1054, 1932. 



90. Pearse, A. G. Everson: J. Clin. Path., 4:1, 1951. 



91. Turcliini, J., Castel, P., and Kien, K.: Trav. soc. chim. biol., 35:1329, 

 1943; Turchini, J., Castel, P., and Kien, K.: Montpellier med., 23-24:599, 

 1943; Turchini, J., Castel, P., and Kien, K.: ibid., 25-26:396, 1944; Tur- 

 chini, J., Castel, P., and Kien, K.: Bull, d'bistol. appHq. a la physiol., 21:124, 

 1944; Turchini, J., and Gosselin de Beaumont, L. A.: Compt. rend. Soc. de 

 biol., 139:584, 1945; Kien, K., and Sentein, P.: Compt. rend. A. anat., p. 

 264, 1947; Turchini, J., Castel, P., and Kien, K.: Compt. rend. A. anat., 

 p. 456, 1947; Turchini, J., and Kien, K.: Compt. rend. A. anat., p. 391, 

 1948; Turchini, J., Castel, P., and Kien, K.: Compt. rend. Soc. de biol., 

 142:1277, 1948; Turchini, J.: Exper. Cell Research, Suppl., 1:105, 1949; 

 Turchini, J., and Kien, K.: Xllle Congres internat. de zool. Paris, p. 207, 

 1949. 



92. Hillary, B. B.: Bot. Gaz., 101:276, 1939. 



