STUDIES IX THE EXPERIMENTAL ANALYSIS OF SEX. 259 
material in this organ. Now just as the blood varies at 
different periods in respect of its fat contents, so the liver 
shows marked variation. Sometimes the liver is opaque 
white or yellow, and this is a sign that a large quantity of fat 
is stored up in the fat-cells. Extraction and estimation of 
the quantity of ether-soluble material, after saponification 
and treatment by the method giveu above for the blood, has 
shown that the liver under these circumstances contains 
about 12 per cent, of its total weight of fatty material. 
Sometimes, however, the liver is seen to be brown in colour 
and transparent ; in this condition the fat-cells are 
comparatively poorly supplied with fat, and certain other 
cells, the ferment-cells, are more conspicuous. Analyses of 
the liver under these conditions show that the fat contents 
has sunk to 6 or even 4 per cent, of the total weight. This 
state of fat-exhaustion can be artificially produced by pro- 
longed starvation. Fasting for eleven days gave a fat 
estimation of 7*38 per cent., for seventeen days 4*46 per 
cent. 
Now observation has shown that when the liver is com- 
paratively free from fat the blood is always colourless, and 
couverselv when the blood is charged with lipochrome a large 
quantity of fat and lipochrome is present in the liver. It is 
not, however, the case that the presence of abundant fat in 
the liver is always accompanied by the presence of fat and 
lipochrome in the blood, and this is in accordance with 
expectation on the supposition that the fat and lipochrome is 
first formed and stored in the liver and then as occasion 
requires transferred by the blood to the skin or ovary as the 
case may be. It has been observed that the liver of the 
female at the time of the ripening of the ovary is always rich 
in fat and lipochrome, so that we can hardly avoid the 
conclusion, so plausible on general grounds, that the seat of 
origin of the fat and lipochrome in the blood is the liver. 
We now pass on to consider the effect which the parasite 
Sacculina exerts upon the properties of the blood and liver 
which we have described above. Robson and myself agree 
