514 
were also many well-formed crystals, orange crystal-plates with 
rounded ends and aggregates of the same erystal-plates. The crystals 
give the various colour-reactions of carotinoids and the same is the 
case with the orange globules, in proof, that all the carotinoid has 
not yet crystallized out. 
The formation of crystals by the potash method is easily explained. 
In the living plant the carotinoids occur in solution. They are dissolved 
in a fluid, fatty substance. When Moriscu’s reagent is added the plas- 
tids are destroyed and the fluid substance forms globules, which are 
coloured orange-yellow or orange by the carotinoid. Morisca’s reagent 
farther brings about saponification and solution. The oily substance 
is saponified and the cells are filled with a solution of the saponi- 
fication-product in which the carotinoid is soluble. This solution is 
diluted by the reagent in which the objects are placed and the caro- 
tinoids, which are not soluble in Momiscn’s reagent, separate in the cells. 
By reason of the above facts, [ assumed that the carotinoids must 
be soluble in soap-solutions. This was indeed found to be the case. 
If, for example, after being washed out with water, preparations, in 
which carotinoids occur in the form of crystals, are placed in soap- 
spirit (Spiritus saponatus Pharm. Nederl. Ed IV without oil of laven- 
der) the crystals dissolve. 
As is evident from the examples described above, the saponification 
of the fatty substance and the separation of crystals sometimes takes 
place rapidly and sometimes very slowly. According to the nature of 
the object minutes, hours, days, weeks, or months are required for the 
separation of the erystals. Among objects which require much patience 
are the following in addition to the ligulate florets of Gazania splen- 
dens those of Hiéracium aurantiacum, Doronicum Pardalianches and 
Taraxacum officinale, in which erystals were observed after 24, 48 
and 74 days respectively. In the ligulate florets of Hiéracium murorum 
and Inula Helenium and in the petals of Viola cornuta no crystals 
were perceived after 60, 39 and 29 days respectively. That the 
carotinoids do not separate out in these last examples, must be attri- 
buted to the fact that the oily substance is not saponified and holds 
the carotinoid in solution. The yellow or orange-yellow globules, 
which are seen in the cells, are coloured blue by sulphuric acid, 
transient blue by bromine water and green by iodine in potassium 
iodide; this proves that the carotinoid is still present. 
I do not think that the long continued action of Moniscn’s reagent 
is accompanied by any disadvantage. I have no indication that the 
carotinoids are destroyed by it and often fine crystallisations are finally 
obtained. I have tried Monisca’s potash method in about 40 cases and 
