1026 
Journal of Agricultural Research 
Vol. XXXI, No. 11 
some of the vitamin A of food products with which it may be inti¬ 
mately mixed. It further suggests that the destruction of vitamin A, 
under the conditions here obtaining, proceeds gradually over a period 
of several days. 
SUMMARY 
Three experiments with rats bearing upon the characteristics of 
rancid lard as a food are reported. The lard used was more intensely 
rancid than would anywhere have been tolerated for human con¬ 
sumption, and probably more rancid than would be acceptable for 
animal feeding. It was also employed in larger proportions than 
those in which fat is generally used in the rations of man or beast. 
The results may be summarized as follows: 
Under the conditions of these experiments, rancid lard, though 
clearly inferior to sweet lard as a ration component, did not seem to 
be actually toxic to the white rats receiving it. 
The inferiority of rancid lard as a food product appeared to be 
due to its ability to destroy the vitamin A of the rations with which 
it was admixed. This destruction appeared to occur gradually over 
.a period of several days, and was presumably due to the oxidation of 
the vitamin A by the organic peroxides of the rancid lard. 
When the vitamin A was fed separately from the lard, the* males 
receiving the rancid lard seemed to require more vitamin A than did 
males receiving a corresponding ration containing sweet lard. 
