APRIL. 8, 1915 | 

NATURE 
147 

as cattle food in the South of France. If the 
new industry is to succeed here it will have to | 
be supported by the agricultural interests. 
Some idea of the magnitude of the nut-oil in- 
dustry is gained from the following figures :—The 
world’s production of coco-nut and copra oil 1913- 
1914 is estimated at 377,000 tons, of which 300,000 
tons were used in Europe. The total supply of 
hard vegetable fats (coco-nut and palm kernel oil) 
available for margarine is said to have been 
240,000 tons in 1913, and perhaps 300,000 tons 
in 1914. Out of 347,000 tons of hard fat stated 
to be used for margarine in 1913, 204,000 tons 
were vegetable, and the quantity of vegetable fat 
used in 1914 may have amounted to 300,000 tons, 
1.e., the total visible supply. There is little 
wonder that there has been a great increase in 
the price of these oils, and that the tropical 
sources of palm tree oils are being widely 
exploited. Nearly all tropical countries report an 
increase in the area under coco-nuts, or an im- 
provement in the methods of dealing with the 
existing trees, and in the machinery for making 
copra or extracting the oil, which is still very 
primitive and inadequate. 
The nut oils resemble butter and differ from 
all other fats in containing a large proportion of 
fatty acids of low molecular weight. Butter con- 
tains acids from butyric acid upwards in the homo- 
logous acetic acid series; the chief constituent of 
nut oils is lauric acid. Few of the remaining 
oils of commerce contain acids lower in the series 
than palmitic acid. 
In preparing vegetable fats for the market the 
all-important consideration is the careful selection 
of the raw materials. The oil is worked as fresh 
as possible, so that the best results are obtained 
when the seed is pressed in this country. It should 
be understood that the refining process involves 
no treatment with chemicals except the agitation 
with weak alkali to remove the fatty acids present. 
The importance of fats in the dietary requires 
no emphasis; on the other hand, it is questionable 
whether all fats have the same value as food | 
materials. Fats, being glycerides, are decom- 
posed in their passage through the alimentary | 
system into glycerol and fatty acids. The de- 
composition is effected through the agency of an 
enzyme, lipase, so that the digestibility of the fat 
depends on the rate at which it is attacked by the 
enzyme. The fat has to be brought into a suitable 
state of emulsification before the enzyme can act 
on it; and though the factors controlling this state 
are still somewhat obscure, it is above all 
important that the fat should melt readily at the 
temperature of the body. Hence the comparative 
digestibility of a fat is in the first place based on 
its melting-point. Stearine is badly digested, 
liquid oleine is readily digested. The addition of 
sufficient oleine to stearine so as to reduce the 
melting-point of the mixture renders the stearine 
also digestible. Consequently the all-important 
point which margarine makers keep in view is the 
melting-point of their product in relation to the 
body temperature; if this is correct the material 
NO. 2271,. VOL. O5|| 

may contain some ingredients of a considerably — 
higher melting-point. 
It is of interest to note in this connection that 
vegetable fats are composed to a great extent of 
ated tri-glycerides—that is, the glyceride con- 
tains more than one fatty acid in its molecule, 
whereas normally one molecule of glycerol is 
coupled with three molecules of the same fatty 
acid. Experience teaches that the melting-point 
of the fat will be greatest when these are “all the 
same. The melting-point of the fat is further in- 
fluenced by the fact that it consists of a number 
of different glycerides, both * simple and mixed. 
Since mixing of fats has the result of altering the 
relative proportions of these it is evident that the 
final melting-point of a mixture cannot be pre- 
dicted on theoretical grounds, and it is agreed 
that butter substitutes of suitable melting-point 
are as digestible as butter. 
It is customary to measure approximately the 
nutritive function of a food by its energy value in 
calories per pound, but modern research has 
shown this method to be inaccurate in two 
respects. In the first place it ignores the quality 
of the food; secondly, 
traces of the vitamines. 
It has been found by experimenting with isolated 
food substances that diets otherwise sufficient in 
energy value fail to maintain growth and health 
unless they contain certain substances hitherto 
unrecognised, but which have been named vita- 
mines. The work in this field is of recent date, 
and is vitiated by the usual errors accompanying 
premature publication—indeed, much of it has been 
recalled already, but it would appear that the vita- 
mines are of lipoid nature. They are present in 
butter, but not in the refined fats which are used 
for butter substitutes. How far this difference is of 
importance it is difficult to say; probably sufficient 
vitamines are present in the rest of the dietary to 
enable them to be dispensed with in the fat. 
The question of quality is of more importance, 
though it has hitherto largely escaped attention. 
The individual fatty acids probably differ in 
their value in somewhat the same way as the 
different amino-acid constituents of the proteins 
have been shown to do, though to a less extent. 
The lower fatty acids in butter are perhaps speci- 
ally important in making it of more value than 
olive oil, which is composed mainly of oleic acid, 
or than fats composed entirely of palmitic and 
stearic acids. Nut oils, however, resemble butter 
in containing a proportion of the lower acids, and 
hence their use in butter substitutes is entirely 
rational from the point of view of nutritive value. 
In the foregoing the nature and preparation of 
materials available for use as butter substitutes 
have been indicated and their food value discussed. 
When it is remembered that the new industry is 
tinder rigid scientific control and conducted with 
a cleanliness mostly unknown in the butter in- 
dustry, and, moreover, that it has made edible 
fats available for the masses at half the price of 
butter, it must be proclaimed as yet another of 
the achievements of science in the service of man. 
it neglects the presence in 
