28 THE PRESIDENTIAL ADDRESS. 
Some years ago it had been discovered that if dried seeds are germi- 
nated, a quantity of the anti-scorbutic vitamin is produced by the act of 
sprouting. This was done. The dried peas and beans were soaked in water 
and then spread out in shallow layers, to cause them to sprout, which they 
readily did in the warm climate. The germinated seeds were then issued 
to the Indian troops and cooked in the usual way. As a result of this simple 
procedure the scurvy completely disappeared. 
In regard to the British troops it was known that the anti-beri-beri 
vitamin is contained in large quantities in certain cells, and notably in 
yeast cells. A small quantity of this substance in the form of marmite was 
added to the soldier’s diet of bully-beef and biscuits, and the beri-beri 
in like manner disappeared. 
It may seem strange that the conception of the rédle of vitamins in 
nutrition should have come first from the pathologist, and should not have 
emerged from the important advances in our knowledge of the physiology 
of nutrition which were made during the second half of the last century. 
The physiologists were preoccupied with the chemical composition of 
food-stuffs and their value for supplying energy and supporting growth, 
and with the necessity for supplying the requisite number of calories in a 
diet, distributed appropriately among proteins, fats, and carbohydrates, 
with adequate selection of mineral salts. It was only when these researches 
led to experiments in which animals were fed upon various mixtures of 
purified food elements that the investigators in this field began to realise 
that their repeated failures to rear animals upon such carefully arranged 
diets were not due to accident. The truth was suspected by Lunin in 1881, 
but it was not until 1912 that Hopkins published the classic experiments 
which proved the fact beyond a doubt. In the course of work along the 
same lines in the United States, McCollum and Davis in 1915 rediscovered 
Vitamin: B, and, in addition, a third essential dietary constituent, a fat- 
soluble vitamin, present in butter-fat and certain other fats of animal 
origin, especially in cod-liver oil and other fish oils. This vitamin is known 
as fat-soluble Vitamin A. 
Rickets as a Deficiency Disease. 
The discovery of the fat-soluble vitamins proved to be of great import- 
ance in elucidating the etiology of this disease, which had for long been an 
unsolved problem. Some authorities had erroneously considered it to be an 
infectious disease, like tuberculosis. Another school held the so-called 
Domestication Theory, that it was caused by unnatural surroundings, 
involving a want of sunlight, fresh air, and exercise. A third considered 
