PROBLEMS OF MODERN SCIENCE 



the pioneer in this country on vitamin research, 

 fed his experimental animals on physiologically 

 correct amounts of purified foodstuffs, but they all 

 sickened and died, not because the food was poison- 

 ous, but because it lacked these accessory factors. 

 He then, in a similar batch of animals on the same 

 diet, added daily a small amount of natural food, 

 viz., about a teaspoonful of milk, an amount which, 

 as regards its actual value for nutriment and energy 

 supply, is negligible. Nevertheless this quantity 

 was quite sufficient to convert the otherwise useless 

 diet into an efficient one, on which the animals 

 were able to grow, thrive, and multiply. The 

 milk was, owing to the vitamins it contained, able 

 to bring about this happy result. 



Let me take my second example, a still more 

 striking one, from the work my colleague Dr 

 Drummond is carrying out now in special reference 

 to cod-liver oil, which is particularly rich in the 

 A (the fat-soluble) vitamin. I say particularly 

 rich, but all these terms are relative. The abso- 

 lute quantity present must, in terms of ounces or 

 even grains, seem unimportant. There are many 

 brands of cod-liver oil in the market, and those 

 which are specially lauded by their makers are 

 those which are refined so that their appearance 

 and taste are made more agreeable. Refining is 

 a drastic process, and vitamins are delicate and 

 are injured or destroyed by high temperatures 

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