SCIENCE AND INDUSTRY. 
—those portions which have a low melting point—while the other por- 
tions—-those that have a high melting point—proved entirely ineffec- 
tive. This fact assists in explaining why beef fat, which also contains 
small quantities of this substance, is much less effective in its growth- 
promoting powers than the butter-fat. The liquid portion in the beef — 
fat is relatively small. 
Fat-Soluble A Not Affected by Pasteurization, Neutralization, or - 
Age.—Additional experiments showed that the fat-soluble A substance — 
is of a stable nature, and that it is neither destroyed, nor its growth- 
promoting and curative effect lessened by heat, saponification, or age. 
Butter-fat boiled with live steam for several hours did not lose its 
biological properties. This is important, because it demonstrates con- 
clusively that the pasteurization of cream does not rob the resulting 
butter of its growth-promoting and curative properties. Pasteurized 
cream butter is equally valuable, therefore, from the dietary stand-point 
as raw cream butter. ; 
Butter-fat or butter, when completely saponified into a soap by ad- 
mixture of alkali in excess, fully retains its growth-promoting and cura- 
tive properties. Butter soap so made, when fed to the rats, had the same 
biological effect as normal butter or pure butter-fat. This fact is 
important, because it removes every vestige of doubt that the reduction 
of the acid in sour cream by the use of an alkali, as practised in so- 
called neutralization of sour cream, in no way destroys or weakens 
the growth-promoting and curative properties of butter- Butter made 
from sour cream that has been neutralized has equal dietary value as 
butter made from cream that was not neutralized. Age does not change 
the biological value of butter. The changes which butter undergoes 
in storage fail to deprive it of its growth-promoting and curative effect. 
Butter-fat held in the cold and at room temperature, in the ight and in 
the dark, for ten months, when subsequently fed to rats which had 
ceased to grow and had developed the characteristic sore eyes as the 
- result of the absence in their diet of the fat-soluble A, brought about — 
resumption of growth to normal stature, and recovery and healing of the 
eyes. The biological potency in all samples of butter-fat held in storage 
was retained, and was equal to that of fresh butter or fresh butter-fat. 
This fact is important, because it furnishes indisputable proof that 
storage butter, relative to biological properties, is equally wholesome as 
fresh butter. 
Other Sources of Fat-Soluble A.—The only substances in which the 
fat-soluble A has been found, other than butter and butter-fat, are the 
fat contained in the yolk of the egg, cod-liver oil, leaves of plants, and 
the fat of the vital organs. 
_ So-called Butter Substitutes cannot take the Place of Butter—This 
discussion makes it clear that there is no substitute for butter. So- 
called butter substitutes, all of which are largely made up of vegetable 
or animal fats, or both, cannot take the place of butter. They may 
have equal, or nearly equal, calorie value as butter, but they lack this 
most important property, the fat-soluble A, without which the diet is not 
complete. Their substitution for butter in the diet of the family is 
jeopardizing the well-being, vitality, and maximum mental and physical 
_ development and vigour of the child, and to that extent limits the future ~ 
greatness of the nation.” 
; 622 
hh — <tanin dienes 
