BIOLOGY AND MEDICINE—CHANDLER 327 
only within the last decade that they have been obtained in chemically 
pure form, and synthesized. Few people even today realize the im- 
portance of this. Although this country is probably the best fed in 
the world, I do not believe it is an exaggeration to say that 50 and pos- 
sibly 75 percent of the American people do not have optimum amounts 
of all the vitamins they should have. They do not have scurvy or 
beriberi or rickets, but they have a host of minor illnesses or troubles 
that they need not have. Some British authorities have gone so far 
as to say that 99 percent of so-called common illnesses are directly or 
indirectly due to vitamin deficiencies. Allowing 100 percent expansion 
for enthusiasm, the figue is still impressive. 
The common effects of vitamin deficiencies are such things as night 
blindness, susceptibility to colds, unhealthy teeth, poor appetite, 
gloominess, nervousness, and a tendency to fly into tantrums. An 
abundance of vitamins leads not only to a state of superhealth in people 
who have always considered themselves reasonably healthy, but it is of 
great help in recovery from acute or chronic diseases, repair of wounds, 
and resistance to infection. Even yet, many medical men tend to look 
upon synthetic vitamins as medicine rather than supplementary food, 
but gradually this is changing, and it is encouraging to see more and 
more foods fortified by added synthetic vitamins. Because of. this 
and the more even distribution of vitamin-bearing foods by rationing, 
the general level of nutrition in England, in spite of several years of 
war, is better than it has ever been before. It is becoming more and 
more so in this country too. 
The definition of medicine includes the prevention of disease as 
well as its cure and alleviation. Some attempts at preventive medi- 
cine were made when disease was supposed to be caused by demons, 
for it was a natural inference that if the demons could be ejected they 
might also be prevented from entering. With the development of 
the humoral theories, preventive medicine was almost completely 
forgotten, since no one had even guessed as to how the humors could 
be kept in order before they got out of balance. Prevention of dis- 
ease is a phase of ecology, and involves knowledge of normal bodies 
and their relation to their environment, including climate, atmosphere, 
and geological formations, as well as relations to such fellow creatures 
as rats, mosquitoes, lice, hookworms, amoebae, and bacteria, to say 
nothing of viruses. . 
It is only in very recent times that anything whatever has been 
known about this phase of medicine. Only in a few instances have 
the processes of trial and error that led to curative and alleviative 
procedures led to practices that prevent disease. One of the first 
great triumphs in curative medicine was the discovery, in 1640, of 
the value of extracts of cinchona bark as a cure for malaria, but it was 
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