767 
them for some time a lipochrome-poor diet, the lipochrome disappears 
completely from their serum. 
3. Cows, pasturing in the meadow, yield milk that is much richer 
in lipochrome than with stall-feeding (relationship of the colouring 
materials of the grass and those of the bloodserum). Also the blood- 
serum of these cows contains more lipochrome than that of stable-cows. 
These conclusions are completely in accordance with PALMER’s 
findings. 
When prosecuting our inquiry, it appeared to be necessary to 
determine quantitatively or to estimate the amount of lipochrome in 
bloodserum, plant-parts, and animal tissues. This we attempted to 
do colorimetrically. 
For comparison-liquid we used a '/,, °/, aqueous solution of potas- 
sium-bichromate; the lipochrome was invariably examined in an 
ether-solution. It is necessary for similar quantitative estimations to 
use always the same solvent, the colour of an equal quantity of a 
detinite lipochrome varying in different solvents. 
The determination of the lipochrome-content of bloodserum takes 
place in the following way: 
1 or 2 ee. serum is precipitated with the same volume of 96 °/, 
alcohol. The liquid is centrifuged, the precipitate extracted with 1 
resp. 2 ce. of ether. This yields an (impure) lipochrome solution in 
ether of the same concentration as in the original serum. 
When there is a high lipochrome content, the precipitate is once 
more extracted with an equal quantity of ether, after which the 
value must be multiplied by 2. 
When there is a large amount of bilirubin the ether-extract is 
washed with a few drops of very dilute sodium hydrate solution. 
With the aid of Herrice's colorimeter we made a comparison 
with the potassium-bichromate solution. 
The lipocbrome-content of parts of plants and of animal tissues 
was determined as follows: 
Parts of plants were boiled with alcohol, and subsequently extracted 
in a mortar with aleohol and ether, until the extract was colourless. 
The extract is filtered, then the colouring matter is, by the additiou 
of water, transferred to ether. With this operation other vegetable 
pigments remain in the lowermost dilute alcoholic layer. If necessary 
this layer is still extracted with ether, and the ether extracts are 
given a proper intensity of colour by evaporating them down with 
caution. By the addition of a few drops of absolute alcohol a clear 
ether-extract is obtained, of which the volume and the colour is 
determined. Let a be the parts of plants in grammes, 6 the amount 
