BUTTER V. MARGARINE. 
Butter v. Margarine. 
‘Experimental Feeding Trials. 
The latest work of Otto F. Hunziker, B.S.A., M.S.A., formerly 
Professor of Dairy Husbandry, Purdue University, which was published 
in February, 1920, supplies the latest information on this much-debated 
subject. The following extracts are submitted for general information :— 
“ BrotocgicaL Properties or Burrer. 
Butter contains Growth-promoting and Curative Properties.—The 
butter-fat of butter contains certain biological properties which are not 
present in vegetable fats, nor in the ordinary animal fats. These proper- 
ties are absolutely essential for an adequate diet. A diet that is lacking 
in these biological properties is inadequate to produce normal growth in 
the young, it prevents well-being of the adult, and gives rise to certain 
deficiency diseases. 
By biological properties is meant those properties, recently discovered 
by McCollum, and subjected to extensive investigation by 
McCollum, Hart, Steenbock, Fink, Hopkins, Osborne, Mendel, and 
other nutrition experts and physiological chemists,- which have to do 
with the life functions of the living organism. These properties cannot 
xs yet be determined by any now known method of chemical analysis; 
their presence has only become recognised by means of experimental 
feeding trials with young animals. 
These feeding trials, largely though not exclusively conducted with 
young white rats, showed that when the animals were put on an arti- 
ficial diet containing all the chemical elements necessary for nutrition, 
both for maintenance and for growth, such as protein, carbo-hydrates. 
fats, and mineral salts, but in which the fat part of the ration consisted 
of a vegetable oil or of lard, the rats would, after a brief period, cease 
to grow, so that they rarely attained more than two-thirds of the normal 
erowth of fully-grown rats. As this diet was continued, they would 
lose weight, and gradually develop sore eyes, which culminated in blind- 
ness and ultimate death of the rats. When, before the death of the 
rats, a portion of the animal or vegetable fat in the ration was replaced 
by butter or butter-fat, they recovered from their disease, gained in 
weight, and resumed their normal growing. 
Fat-Soluble A.—Further experiments, in which the pure butter-fat 
was separated from the butter, and the butter-fat instead of the butter 
_was used to replace a part of the lard in the feed ration, yielded identi- 
cally the same results as in the case of butter, showing, therefore, that 
this growth-promoting and curative property of the butter is located in 
the butter-fat. Being soluble in the butter-fat, McCollum gave this 
unknown substance the name fat-soluble A. 
Fat-Soluble A Present in Liquid Portion of Butter-fat—Osborne and 
Mendel succeeded in concentrating the fat-soluble A substance con- 
iained in butter-fat by fractional crystallization of the fat from alcohol. 
They found that the fat-soluble A substance remains in the oily portions 
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