CAROTINOIDS IN THE PHANEROGAM* 35 



knowledge of crystalline carotinoids accompanying chlorophyll in the 

 chloroplastids. Two groups of pigments were described by him, one 

 characterized by their slight solubility in alcohol and great solubility 

 in benzine, corresponding with one of the properties of carotin, the 

 other group being characterized by their ease of solubility in alcohol 

 and their slight solubility, in benzine, which corresponds with one of 

 the most distinguishing properties of the xanthophylls. No names 

 were proposed by Borodin for his crystalline pigments but lie described 

 in detail the crystal forms and certain properties of two carotins and 

 two xanthophylls. One of the carotins formed orange-red rhombic 

 crystals (he obtained these from the alcoholic extract of Spirogyra) 

 and the other bright yellow needles with a strong violet or rose-red 

 nuance. Of the two xanthophylls one formed straw yellow, ribbon- 

 like scales or dark brown, crooked, branching rods, and the other 

 golden-yellow "navikeln," an English synonym for which the author 

 has not been able to find. The latter were observed especially clearly 

 by Borodin in extracts from parsley (Petroselinum sativum). Borodin 

 regarded the red and violet tinted, benzine-soluble group as widely 

 distributed in all chlorophyllous plants, the red forms being identical 

 with Bougarel's erythrophyll. The alcohol soluble forms were not 

 regarded by Borodin as being so widely distributed, especially the 

 pigment forming the golden-yellow "navikeln." With the exception 

 of the red rhombic-formed crystals in the benzine-soluble group 

 Borodin's crystal forms do not correspond with the carotins and 

 xanthophylls which have since been isolated in pure form by various 

 investigators so it is not known whether they represent forms which 

 were modified by the solvents employed or isomeric carotin and 

 xanthophyll carotinoids not yet isolated in quantity. The latter pos- 

 sibility is not to be disregarded in view of the various yellow chromo- 

 lipoids which are revealed in chloroplastids using Tswett's (1906c) 

 chromotographic analytical procedure. 



Guignet (1885) observed orange crystalline material from extracts 

 obtained by a method similar to that used by Dippel for xanthin. 

 Alcoholic leaf extract in strong alcohol was agitated with one-tenth 

 its volume of petroleum ether (Sachsse (1877) introduced the use 

 of petroleum ether instead of benzene in the Kraus separation) and 

 the green petroleum ether extract agitated with a solution of NaOH 

 in 95 per cent alcohol, leaving a yellow solution from which the crys- 

 talline material was obtained. The pigment was no doubt carotin 

 although no name was proposed for it by Guignet. 



