This discovery of how to separate the hard and soft fats was followed by improved methods for purifying them and later by the process for converting the soft into the hard fats by hydrogenation.  The net result was to put into the hands of the chemist the ability to draw his materials at will from any land and from the vegetable and animal kingdoms and to combine them as he will to make new fat foods for every use; hard for summer, soft for winter; solid for the northerners and liquid for the southerners; white, yellow or any other color, and flavored to suit the taste.  The Hindu can eat no fat from the sacred cow; the Mohammedan and the Jew can eat no fat from the abhorred pig; the vegetarian will touch neither; other people will take both.  No matter, all can be accommodated.

All the fats and oils, though they consist of scores of different compounds, have practically the same food value when freed from the extraneous matter that gives them their characteristic flavors.  They are all practically tasteless and colorless.  The various vegetable and animal oils and fats have about the same digestibility, 98 per cent.,[3] and are all ordinarily completely utilized in the body, supplying it with two and a quarter times as much energy as any other food.

It does not follow, however, that there is no difference in the products.  The margarin men accuse butter of harboring tuberculosis germs from which their product, because it has been heated or is made from vegetable fats, is free.  The butter men retort that margarin is lacking in vitamines, those mysterious substances which in minute amounts are necessary for life and especially for growth.  Both the claim and the objection lose a large part of their force where the margarin, as is customarily the case, is mixed with butter or churned up with milk to give it the familiar flavor.  But the difficulty can be easily overcome.  The milk used for either butter or margarin should be free or freed from disease germs.  If margarin is altogether substituted for butter, the necessary vitamines may be sufficiently provided by milk, eggs and greens.

Owing to these new processes all the fatty substances of all lands have been brought into competition with each other.  In such a contest the vegetable is likely to beat the animal and the southern to win over the northern zones.  In Europe before the war the proportion of the various ingredients used to make butter substitutes was as follows: 

AVERAGE COMPOSITION OF EUROPEAN MARGARIN

Per Cent. 
Animal hard fats              25
Vegetable hard fats           35
Copra                       29
Palm-kernel                  6
Vegetable soft fats           26
Cottonseed                  13
Peanut                       6
Sesame                       6
Soya-bean                    1
Water, milk, salt             14
___
100

This is not the composition of any particular brand but the average of them all.  The use of a certain