The Diffusion of Pigments from Fat. 73 
200 c.c. of liquid passed through the upper orifice into a graduated 
cylinder which was supported underneath it to catch the overflow. 
The authors are engaged in a study of various relationships 
that are suggested by the demonstrated phenomena. 
43 (568) 
A demonstration of the diffusion of pigments from fat 
through rubber into fat. 
By WILLIAM J. GlES. 
[ From the Laboratory of Biological Chemistry of Columbia University, 
at the College of Physicians and Surgeons, New York.] 
The author has found that many fat-soluble pigments, such as 
Sudan III and Scarlet R, readily diffuse from solid and liquid fats 
through rubber into various solid and liquid media, among them 
both solid fat and oil. Thus, when Sudan III is dissolved in 
melted lard, the red liquid poured into a rubber bag, the bag sup- 
ported in melted lard in a bottle, and the apparatus promptly 
immersed in ice water — the fatty matter will congeal before any 
sign of pigmentary diffusion occurs, but, in a few hours, a reddish 
tinge will develop outside of the bag, and on each successive day 
for several weeks further extension of the pigmented matter may 
be witnessed, until the whole of the external lard is deeply 
suffused with red. This process takes place quite rapidly when 
the lard and apparatus are kept in a thermostat at 40 0 C. 
The demonstrations were intended to exhibit a few instances of 
such pigmentary diffusions as occur speedily enough at room tem- 
perature to yield positive results within an hour. The appended 
Contents of the Rubber Bag-. 
Nature of the 
Liquid in which 
the Bag was 
Result. 
Oil. 
Pigment. 
Suspended. 
I 
Olive oil. 
Scarlet R. 
Olive oil 
Visible diffusion of the pigment oc- 
curred promptly. 
2 
Cocoanut oil. 
Scarlet R. 
Cocoanut oil. 
Visible diffusion of the pigment oc- 
curred promptly. 
3 
Lard oil. 
Sudan III. 
Lard oil. 
Visible diffusion of the pigment oc- 
curred promptly. 
4 
Paraffin oil. 
Sudan III. 
Paraffin oil. 
Visible diffusion of the pigment oc- 
curred promptly. 
5 
Olive oil. 
Sudan III. 
Ether. 
Visible diffusion of the pigment oc- 
curred almost immediately. 
