VITAMIN B (B,) 93 



the earlier data on account of failure to prevent the animals from 

 having access to their excreta, reinvestigated the vitamin B content 

 of two varieties of white potatoes and found them to be considerably 

 less rich in this vitamin than previously reported. Good growth was 

 secured only when potatoes constituted at least 80 per cent of the diet. 

 They concluded that the white potato can not be depended on safely 

 to make good any considerable deficiencies of vitamin B in other 

 articles of the diet. Possibly a repetition of much of the earlier work 

 on the vitamin B content of other foods would tend to lower the 

 values assigned. This, however, would not necessarily invalidate com- 

 parisons of the relative values of different foods when tested by the 

 same methods. Steenbock and Gross (1919) reported the sweet potato 

 as containing less vitamin B than carrots, rutabagas, or dasheens of 

 which 15 per cent sufficed to make the food mixture adequate. Osborne 

 and Mendel (1919c, 1920a) found spinach, cabbage, carrot, turnip, 

 onion, beet leaves or beet stems to contain about twice as much vitamin 

 B as beet roots, about half as much as tomato and one-fourth as 

 much as yeast when calculated on the dry basis. In this comparison 

 the amount of tomato was 0.5 grams daily. Osborne and Mendel 

 (1922) found green asparagus to be very rich, the minimum daily 

 requirement approximating 0.2 grams of the dried material equivalent 

 to 2.2 grams of fresh. Corresponding values for other vegetable mate- 

 rials on the dry basis were blanched celery 0.5 to 0.8 grams, and 

 lettuce and parsley 0.4 grams. These comparisons have all been on 

 the dry basis, with growth of rats as the evidence of relative amounts 

 of vitamin B in the foods tested. As determined on the fresh basis 

 and with maintenance for a given period instead of growth as the 

 criterion, the vitamin B values of fresh vegetables other than greens 

 are not strikingly different. The values reported by Sherman (1926) 

 in terms of the older units per gram are string beans 0.35, cabbage 

 0.35-0.5, carrot 0.3, onion 0.2, potato 0.3, tomato 0.3-0.6, and turnip 

 0.3. Compared with these figures spinach has a value of 0.6-0.8 and 

 according to Burton (1928) collards and turnip greens have even 

 higher values. Preliminary studies at the Kentucky Experiment Sta- 

 tion have shown kale and mustard greens to be rich in vitamin B, 

 Quinn, Burtis and Milner (1927) have recently shown string beans 

 and green peppers to be equal to lettuce or cabbage but not as rich 

 as spinach in vitamin B. 



Fruits. — Compared in the fresh fluid form, orange, lemon, and 

 grapefruit juice were found by Osborne and Mendel (1920d) to con- 

 tain about the same concentration of vitamin B as they had reported 



