513 
or parts of them are placed in alcoholic potash containing 40°/, by 
volume of alcohol and 20°/, by weight of potassium hydroxyde ; 
they are left in the mixture for several days while light is excluded, 
until all the chlorophyll has been extracted. With green leaves the 
potash method gives good results, but also in many other cases, for 
example, with etiolated, autumn, and variegated leaves, flowers, 
fruits, algae, ete. We may assume that generally the carotinoids are 
separated in those cells in which they occur in the living plant. 
Sometimes the carotinoids wander and form aggregations of crystals 
in apparently arbitrary places or outside the objects. As a rule the 
method gives positive results; only in a few cases does it fail. 
In order to obtain an idea of the way in which the erystal-formation 
takes place, I have in a few cases studied the effect of Mo.iscn’s 
reagent on the living material under the microscope. The crystallisation 
will be illustrated by a few examples. 
Large yellow plastids are found in the corolla of Calceolaria rugosa. 
The carotinoid occurs dissolved in a substance, fluid and easily 
saponifiable, which forms a yellow peripheral layer in the plastids. 
On the addition of Moztscn’s reagent the plastids sometimes form 
yellow globules with a sharp edge, which quickly change into globules 
or masses which show a less well-defined contour and are products 
of saponification. Often saponification proceeds still more rapidly, so 
that globules with sharp outline are no longer seen, but the saponi- 
fication-products appear immediately. They dissolve and out of the 
solution there grow in a few minutes orange-yellow acicular or narrow 
band-shaped crystals, often very long and strongly curved and some- 
times fissured. 
In the ligulate florets of Gazania splendens large orange-coloured 
plastids occur in which can be distinguished globules that are in 
constant movement. When Motiscn’s reagent is added they rapidly 
form orange balls with sharp outline. These arise out of the union 
of the globules described above. The phenomenon is not the result 
of saponification, as Koni.*) assumes, for warming in water or a 
stay in dilute spirit (70°/,) has the same effect. In my opinion it is 
caused by the cells dying and the plastids losing their structure. In 
Gazania splendens saponification of the globules formed proceeds very 
slowly. After being in Moziscn’s reagent for 20 days (in vitro), I 
saw only orange globules in the cells which were coloured dark-blue 
by sulphuric acid. When I investigated the flowers after 24 days, 
I again found many orange globules, but at the same time there 
SEG, Korg, 1. cxyp.-122. 
34 
Proceedings Royal Acad. Amsterdam, Vol. XV. 
