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very doubtful whether the vegetables would retain any anti- 

 scorbutic value after this treatment. 



According to experiments of Delf * (191 8), addition of small 

 amounts of citric acid to the cabbage-leaves before cooking, or 

 to the cooking water in the case of sprouted whole lentils, only 

 increased the destruction of anti-scurvy vitamine involved in 

 the cooking. This is an unexpected result, since acid fruit 

 juices such as lemon and orange are better able to withstand 

 the effect of heat than are the juices of vegetables {cp. Table 

 IV). 



TABLE IV 

 Effect of Heat on expressed Fruit and Vegetable Juices' 



In the present state of our knowledge, therefore, it is safe 

 to say that green vegetables should be cooked in an open vessel 

 until just tender, in fast boiling water, or steamed over water 

 without addition of either acid or alkali to the water. By the 

 former method a better colour is obtained than by the latter, 

 but there is more loss owing to exudations from the cabbage 

 into the water. Salt may be added if desired, for this does 

 not appear to cause increased destruction of the vitamines. 



The experiments of Givens and Cohen " suggest that the 

 anti-scorbutic value of root vegetables, such as carrots, may- 

 vary with age, the young carrots being more powerfully anti- 

 scorbutic than the older, and the freshly gathered older 

 carrots superior to those which have been stored. Young 



