A cow showing the character- 

 istic symptoms of so-called 

 "alkali disease", which killed 

 many army horses eighty 

 years ago. The cause of this 

 disease has been traced only 

 in recent times to the eating 

 of grain or other plant stuff 

 grown on land containing 

 an excess of selenium. The 

 selenium poisoning results in 

 a poor coat, bald tail, and 

 elongated and split hoofs 



Uni I Dept. of Agriculture 



AN EXAMPLE OF SELENIUM POISONING 



either. Recent experiments have suggested that by keeping the fluorine in- 

 take at a certain level it may be possible to prevent caries, which is one of the 

 most common "disabilities" in our population; but this amount of fluorine 

 is not enough to cause mottling of the enamel. 



Experiments have shown that boron, gallium, manganese, aluminum, 

 and other elements play a role in the growth or activity of some organisms, 

 although they are present in minute quantities. It is possible, however, that 

 the various species could thrive in most cases just as well — if in a some- 

 what different manner — without all these rare elements. 



What Are Vitamins? 



How the Sailor Became a Limy During the centuries before the Chris- 

 tian era, when slavery was common, outbreaks of "epidemic" diseases were 

 not rare. Some of these "visitations of the gods" spread to all portions of 

 the population. Others, however, seemed to be restricted to the poor masses. 

 Hippocrates (430-370 b.c), often called "the father of medicine", described 

 one such disease; and from his descriptions we can recognize "scurvy" as 

 the cause of the great distress. 



This disease appeared among the crusaders and on the long sea voyages 

 that preceded and followed the discovery of America. Jacques Cartier, the 

 French explorer who discovered the St. Lawrence River, lost 25 of his men 

 in the winter of 1536 through scurvy, and many others were sick. An Indian 

 told him that a water extract of the leaves of a certain evergreen tree was 

 drunk by his people as a good medicine for that trouble. They cut down a 

 tree and boiled the leaves; and his men recovered. 



Scurvy appeared among the crowded emigrants from old countries seek- 

 ing a home and fresh opportunities in the new. By the seventeenth century 



103 



