O15 
only in the 3 last-mentioned was there no crystallisation of caro- 
tinoid. It is however possible that in these cases also a still more 
prolonged action might have had the desired result. 
TamMMes*) and Koni?) maintain that all the crystals, which are 
obtained by the potash method consist of carotin, however they may 
differ in colour and shape. The colour would only depend on the 
thickness of the crystals and of the angle at which they are seen. 
Brcke *) however, considers as a result of crystallographic investiga- 
tions that the erystals obtained by Mo.iscu’s method are not identical. 
I myself have come to the following conclusions. Before proceeding 
] wish to remark that the names of the colours which I use are in 
agreement with those of KriNckKsiroK et Varerrw’s Code des Couleurs, 
1908. Often the numbers, given to the colours in the book, have 
also been mentioned. 
In many cases the crystals differ greatly in colour and shape. In 
general, with respect to the colours the crystals can be arranged in two 
groups, namely, orange-red and red (Kl. et V. 91, 76, 51, 46) to 
which the violet-red (Kl. et V. 581) of the fruit of Solanum Lyco- 
persicum are allied and a second group composed of orange-yellow 
and orange crystals (Kl. et V. 176, 151, 126, 101). The colour is 
also influenced by the thickness of the crystals. Red is always pre- 
sent in the first group, but not in the second. 
However different the shape of the crystals may be, it is still 
true that colour and form are often connected. Among the red 
crystals, as a rule well-developed plates are found which have the 
shape of small parallelograms and sometimes also of rhombs. Generally 
small plates are formed which are several times more long than broad 
or narrower ones which resemble pointed needles. The parallelograms 
and rhombs are often imperfect. Parts may be wanting, angles and 
sides may be rounded. Very often the red crystals form aggregates. 
The root of Daucus carota and the fruit of Solanum Lycopersicum 
belong to the objects in which carotinoids occur in the form of erys- 
tals. In Daucus the carotin has formed in addition to well-developed 
red parallelograms and rhombs all sorts of other crystals which are 
even curved band shaped. In the tomato lycopin is found in the form 
of red-violet needles. 
The orange-yellow and orange crystals are also very varied. 
Especially in those cases in which the carotinoids crystallize out 
slowly, little plates of crystal are often found which are generally 
1) ] ‚ 242, 244, 
sle G. 2 93 et seq. and p. 67. 
3) ne Moutscu, |. ce. p. 24. 
4 
