388 Keport of the Chemist of the 
The tests applied to the butter were viscosity of its soap solutions 
and its behavior when mixed with subacetate of lead. The first of 
these tests is very sensitive to changes in the composition of butter 
fat. Moreover the soaps from crude cottonseed oil have a high 
viscosity, while those from butter fat are usually low. 
The butter from the cow experimented with was tested February 
25; April 18, 22, 26, 28; May 4, 8, 16, and October 21, with the follow- 
ing results : 
Date Feb. 25. April 18. April 22. April 26. 
Viscosity 65 69 62 73 
Date April 28. May 4. May 8. May 16. Oct. 21. 
Viscosity 61 69 68 65 68 
Feb. 25, when the first test was made, the cow was being fed ensilage, 
with some hay and corn meal. For two weeks preceding April 18 she 
was fed hay with corn meal and wheat bran. From this time until 
into May she received hay with a gradually increasing quantity of cot- 
tonseed meal. The uniformity of this test, before, during and after 
the experiment, shows that very little change in the composition of the 
butter had occurred under decided changes in the character of the 
ration, and is strong evidence that no cottonseed oil was transferred 
to the butter. This will be more apparent when it is considered that 
the viscosity of soap solutions from butter of different cows under 
normal conditions has varied from 50 to over 400: 
"When cottonseed oil is thoroughly mixed with a strong solution of 
basic acetate of lead, and allowed to stand for some time, it changes to 
a peculiar brownish red color.* This reaction is said to be character- 
istic of this oil and serves to detect it when mixed with other fat. 
Pure butter fat treated in this way remains unchanged in color, but 
the addition of a small quantity of cottonseed oil causes it to assume 
a yellow, and if a large quantity is present a brown color. None of 
the butters made from this cow at any time, whatever her feed, were 
affected by this test. 
The negative results of these two tests show beyond question that, 
in this case at least, there was no transfer of cottonseed oil from the 
food to the milk. The same thing is shown by the constant and uni- 
form difference found in butters from different breeds of cows and 
from individual cows in the same herd, all receiving the same food and 
care. These considerations and the general impressions of all of my 
work with butter have led me to believe that the composition of the 
* Zeit. fur Chem., XXII, p. 618. 
