524 
Other methods. 
Kou?) has remarked that possibly other substances also might be 
used to bring about the crystallisation of carotin. He surmises that 
chloralhydrate might be used for the purpose and intends to inves- 
tigate this possibility. When the solvent action of chloralhydrate 
upon the various constituents of cells is considered and it is seen 
that carotin crystals in contrast to those of xanthophyll are fairly 
resistant, then it is natural to suppose that chloralhydrate may 
offer a suitable means of separating carotin as crystals. I have 
experimented with the leaves of Urtica dioica in a concentrated 
aqueous solution (7 in 10) of chloralhydrate. We know from the 
investigations of Wairrsrätrrer and Mira *) that these leaves contain 
carotin and xanthophyll. When I placed a small piece of the 
tissue containing chlorophyll in a solution of chloralhydrate and 
observed it under the microscope, 1 could soon detect changes in the 
chromatophores and the formation of a globule in each cell, which 
gradually dissolved and left behind a small aggregate of red carotin 
crystals. Orange-yellow crystals of xanthophyll were not separated. 
As was to be expected therefore the method is of no use for 
the separation of xanthophyil because decomposition takes place. I 
cannot moreover recommend it for the separation of carotin-crystals, 
because carotin is also attacked by chloralhydrate and small quantities 
therefore may escape observation. 
According to Wisrärrer and Mine *) xanthophyll is “spielend 
léslich” in phenol. Having in mind the solubility of many substances 
in liquefied phenol and having confirmed the fact that carotin dis- 
solves much more slowly than xanthophyll, it occurred to me to try 
liquefied phenol for the separation of carotin or allied carotinoids. I 
used two mixtures, one of 10 parts by weight of phenol in loose 
crystals and 1 part by weight of water, the other consisting of 3 parts 
by weight of phenol in loose erystals and 1 part by weight of glycerine. 
I prefer the latter mixture, because it mixes more quickly with the 
water contained in the objects. I examined the flowers of Erysimum 
Perofskianum, Asclepias curassavica, the leaves of Urtica dioica and 
the ligulate florets of Taraxacum officinale. With petals of Erysimum 
Perofskianum the potash method yielded no beautiful result, and the 
acid method a negative one. I placed parts of the petals in the above 
mixtures between a miscroscope slide and a cover-slip. Under the 
1) 1, c.p. 124. 
2) dep tO: 
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