“…the importance of the vitamine hypothesis has been forced upon us…”
Just four years after experiments in animals began to reveal that small amounts of mysterious compounds were essential to health, Thomas Osborne and Lafayette Mendel, arguably the two most important U.S. nutrition researchers of their time, conceded that vitamins existed and were important.
As they explained in their 1917 scientific paper, “Without the use of some water-soluble accessory substances such as has been demonstrated to be present in milk, “protein-free milk,” yeast, the extract of embryos of certain seeds, animal tissue extracts,” or doubtless in nearly all the commonly used animal or vegetable foods in their natural state, we, in common with many other investigators, have failed to induce growth or even maintenance in such a large proportion of our trials that the importance of the vitamine hypothesis has been forced upon us.”
Osborne and Mendel worked at the Laboratory of the Connecticut Agricultural Experiment Station and the Sheffield Laboratory of Physiological Chemistry at Yale University, both in New Haven.
full text of their paper: The role of vitamins in the diet. J. Biol. Chem. 1917, 31:149-163.