754 
tively a slow process, the action on serum, which renders lipochrome 
accessible for ether or benzene, manifests itself instantly. 
Lipochrome, then, is freed during the first phase of the action of 
alcohol on the protein (precipitation) and prior to the second phase 
(denaturation). 
I doubt, therefore, whether the liberation of lipochrome by alcohol 
is due to a decomposition of a supposed albuminous compound. 
That this alcoholic action may occur, without any question about 
the destruction of an albuminous compound — as in lipochrome 
solutions which are free from protein — is borne out by the following 
experiment. 
A concentrated solution of carotin is prepared by extracting finely 
rubbed carrots with a mixture of alcohol and ether. The ether is 
removed, after which a gold-yellow, alcoholic solution of carotin is 
left behind. When this solution is diluted with water, so that the 
alcohol-content in the mixture is very low, the carotin will not be 
precipitated, nevertheless the solution keeps clear. By evaporation in 
vacuo (if required with gentle heating in the waterbath) the rests 
of alcohol, still left behind, are removed as much as possible. The 
carotin does not precipitate then either, but a solution remains in 
which no solid particles are visible. It passes through the filter 
unchanged. Solutions of a higher concentration are opalescent, those 
of lower concentration are clear. The investigation Prof. Kruyt 
kindly performed confirms that the carotin in this solution is in a 
colloidal condition. It appears, then, that by this procedure we are 
able to solve carotin in water in a colloidal state, although under 
ordinary circumstances it is insoluble in water, as e.g. is also the 
case with mastic, cholesterin and many lipoids. 
However, an attempt to extract this colloidal solution with ether 
fails. Even a two hours’ rapid shaking in the shaking apparatus 
does not enable us to transfer the slightest trace of yellow pigment 
to the ether or the benzene. But as soon as we add to the mixture 
a small amount of alcohol, e.g. some drops to 5 em®* of colloidal 
carotin solution and 3 ecm° of ether, the pigment will pass over 
instantly and quantitatively into the upper layer, whereas the 
lowermost layer is completely decolourized and generally becomes 
rather more opalescent. The best result is achieved, when first some 
drops of alcohol are added to the solution and after this the ether. 
A similar result is obtained when, before carrying out these 
experiments, the fats and the cholesterin are removed from the 
alcoholic carotin solution respectively by saponification and by 
digitonin. 
