"The great changes which the theories of the science of nutrition have undergone in the course of the past few years," we are reminded by Halliburton and Drummond1 of London, "are now being rewarded by valuable practical applications of laboratory results to the great problems of animal nutrition, and the national welfare. Such a problem is that which deals with the determination of the relative value as foodstuffs of dairy butter and its numerous substitutes." These authors have accordingly undertaken to expand our knowledge in this field by a study of the nutritive value of margarins and butter substitutes with reference to their content of the fat-soluble accessory growth substance.
It deserves to be emphasized that the association of food hormones or vitamins with certain naturally occurring fats, whereby somehow they promote growth in experimental animals, was originally described by American investigators: McCollum and his associates at the University
A PROBLEM CONCERNING EDIBLE FATS. JAMA. 1917;LXIX(22):1876–1877. doi:10.1001/jama.1917.02590490040009