192 THE VITAMINS 



in an important phase of dried fruit nutritive value, appears to be derived from 

 the sulfur dioxide treatment during drying." 



Craven and Kramer (1927) reported no difference in the vitamin 

 C content of ripe Kieffer pears grown locally (Kansas) or obtained 

 from California, and no loss of potency on storage in a fruit storage 

 room at a temperature of 40° F. from February to April. They found 

 the minimum protective dose of the raw pear to lie between 10 and 

 15 grams and concluded that pears of this variety are about one-fourth 

 as rich in vitamin C as oranges. Apparently complete destruction of 

 vitamin C resulted from the open-kettle method of home canning and 

 considerable destruction by the cold-pack method. 



In a later cooperative study Kramer, Eddy and Kohman (1929) 

 found that Kieffer pears canned by commercial processes while still 

 hard and green retained most of their vitamin C. The fully ripened 

 pears when canned did not afford full protection against scurvy in 

 doses as high as 30 grams. Bartlett pears were even lower in vitamin 

 C in the ripe state than Kieffer pears and no great difference could be 

 noted between the potency of the raw and canned product. A consider- 

 able loss in vitamin C was attributed to the ripening and mellowing 

 process. 



Chick, Hume and Skelton (1919) were led to investigate the value 

 of some Indian dried fruits through the fact that these foods enjoyed 

 the reputation of antiscorbutics in India and have been relied upon to 

 some extent by native Indian troops. They concluded that dried tama- 

 rinds, cocum and mango possess significant but not large quantities 

 of the antiscorbutic vitamin, that weight for weight these fruits are 

 superior to carrot, cooked potato, or raw meat juice, but greatly in- 

 ferior to raw cabbage, germinated pulses or the juice of Swedish 

 turnips, oranges or lemons. 



In an investigation carried out at the South African Institute for 

 Medical Research, Johannesburg, to determine the relative antiscorbutic 

 values of the foodstuffs commonly used in the dietary of native workers 

 in the Rand Mines, Delf (1921, 1922) found the native navel oranges 

 and tangerines to be as rich in vitamin C as hitherto reported for 

 oranges, 1.5 cubic centimeters daily being the minimum protective dose 

 for guinea pigs. Corresponding values for other fruits were 2.5 cubic 

 centimeters of pineapple juice, representing 9 grams of the whole fruit 

 and 5 cubic centimeters of papaya {Carica papaya) juice or 10 grams 

 of the fresh fruit. From two to three cubic centimeters of the juice of 

 peaches afforded protection early in the season, but as the peaches 

 ripened they proved less effective. 



