110 CAROTINOIDS AND RELATED PIGMENTS 



a red xanthophyll-like pigment whose exact relation to the caro- 

 tinoids remains to be determined. 



The red pigment of Euglena sanguined was first isolated by v. 

 Wittich (1863) and later by Garcin (1889) and Kutscher (1898). 

 V. AVittich obtained microscopic, garnet colored octahedral crystals by 

 concentrating the hot alcoholic extract or by adding alcohol to the 

 concentrated ether solution of the pigment. The crystals were quickly 

 bleached by chlorine and gave a blue color reaction with concentrated 

 sulfuric acid. The crystal? melted indefinitely between 70 and 120 

 C. They dissolved in hot alkali and the pigment could be recovered 

 from this solution in amorphous form, but without loss of other prop- 

 erties, by addition of acid. Neither Garcin nor Kutscher was able 

 to extract the pigment from Euglena cultures with cold alcohol, but 

 the former obtained orange-red extracts with chloroform, following 

 alcohol treatment, and the latter with boiling absolute alcohol. The 

 pigment extracted by Garcin showed no absorption bands, but dis- 

 solved in concentrated sulfuric acid with a blue color. Garcin pro- 

 posed the name rufin for the pigment. Kut seller's absolute alcohol 

 extracts deposited garnet colored crystals on concentration. The 

 pigment as described further by Kut seller does not seem to be a caro- 

 tinoid because the recrystallized substance melted at 105 C. and 

 exhibited no absorption bands. The crystalline pigment, as well as 

 its alcoholic solution, turned blue on addition of dilute (50 per cent) 

 sulfuric or nitric acids, but alkalies had no effect. 



Besides these more critical studies Krukenberg (1886) found that 

 saponified alcoholic extracts of Euglena would yield a greenish-yellow 

 lipochrome to petroleum-ether or ether" in addition to the red pigment 

 w r hich acetic ether only would extract from the soap. The red pig- 

 ment, according to Krukenberg, showed one absorption band, which 

 is contrary to the statement of the other investigators. The greenish- 

 yellow pigment may have been a true carotinoid inasmuch as evi- 

 dence of carotinoids in Euglena was obtained by van Wisselingh 

 (1915) who secured a positive Molisch" carotinoid test on the eye 

 spots. The chief pigment present, namely, the red one, does not, 

 however, appear to be identical with ay of the known carotinoifls, 

 but resembles more nearly the red carotinins of Zopf. 



The Myxophycece (Cyanophycece) . These constitute a large class 

 of unicellular or filamentous algae without a true nucleus, which 

 inhabit both fresh and salt water and are also found in damp soil, 

 or on damp rocks and tree-trunks, forming dark blue-green patches. 



