UTAH ACADEMY OF SCIENCES 249 
VITAMINES IN RELATION TO NUTRITION. 
BY W. E. CARROLL. 
The adequacy of the human diet has until recently 
been measured by the amount of protein and mineral 
salts and the number of calories it could supply to the 
body during digestion. As investigations progressed due 
consideration has been given such questions as the source 
of the protein in its relation to the kind and amount of the 
amino acid supplied; the distribution of the total calories 
among the protein, carbohydrates, and fats; and the 
maintenance of the proper balance between the acid and 
basic constituents of the mineral ingredients. Many other 
factors have received attention and many dietetic fads 
have been advocated, but at the foundation of them all 
has been the question of how much protine and mineral 
salts are available as building materials, and how many 
total calories does the diet provide. The work of recent 
years, however, has proved beyond question that a diet 
meeting the above requirements may result in nutritional 
failure because of the absence of small amounts of as yet 
unidentified substances called vitamines. 
Even before this discovery was made difficulty had 
been experienced in maintaining laboratory animals on 
rations of purified nutrients which supplied ample protein 
mineral salts, and total energy. The cause of such con- 
ditions was then unknown and the reason back of the 
remedy could not be explained. 
Certain diseases, as beri-beri and scurvy, have been 
common in different countries and under different condi- 
tions for a long time. Attempts to discover a bacterial 
cause for these diseases failed, and the idea gradually 
developed that they were due to one-sided or deficient 
diets. Just what was lacking was not well understood, 
and the reason recovery followed certain changes in food 
