668 



Accessory Food Factors. 



[Oct., 



nursing mother will suffer if her diet becomes deficient in this 

 essential, the adverse effects here are much more rapid owing 

 to the smallness or absence of such reserve supply. 



The factor withstands desiccation for long periods of time. 

 Its resistance to heat is also considerable; destruction takes 

 place very slowly at 100° C. (212° F.) , but is much more rapid 

 in the neighbourhood of 120° C. (248° F.). Tinned foods of 

 all descriptions, with but few exceptions, would therefore be 

 deficient in this vitamine. 



The distribution of this factor in foods is given in the 

 concluding Table. 



(3) Anti- Scorbutic Factor. — The preceding factors are 

 admittedly indispensable for growth as well as nutrition. The 

 third or anti-scorbutic factor is undoubtedly indispensable for 

 normal nutrition of certain species of animals, but in the light 

 of present knowledge it is difficult to say whether it is indis- 

 pensable as a component of a normal dietary for growth, 

 because wide variations occur in the requirements of various 

 species for this substance. 



This vitamine is necessary in a diet for the prevention of 1 

 scurvy, and is found in fresh vegetable tissues and (to a much 

 less extent) in fresh animal tissues. Its richest sources are 

 such vegetables as cabbage, swedes, turnips, lettuce, water- 

 cress, and such fruits as lemons, oranges, raspberries and 

 tomatoes. Inferior in value are potatoes, carrots, French 

 beans, scarlet runners, beetroot, mangolds, and also (contrary 

 to popular belief) lime juice. Potatoes, although classed among 

 the less valuable vegetables as regards anti-scorbutic value, are 

 probably responsible for the prevention of scurvy in Northern 

 countries during the winter, owing to the large quantities 

 which are regularly consumed. Milk and meat possess a 

 definite but low anti-scorbutic value. 



This vitamine suffers destruction when the fresh foods 

 containing it are subjected to heat, drying, or other methods of 

 preservation. 



All dry foods are deficient in anti-scorbutic properties ; such 

 are cereals, pulses, dried vegetables and dried milk. 



Tinned vegetables and tinned meat are also deficient in the anti- 

 scorbutic principle. In the case of tinned fruits the acidity of 

 the fruit increases the stability of the vitamine, and prevents 

 to some extent the destruction which would otherwise occur 

 during the sterilization by heat and the subsequent storage. 



