NUTRITION. 377 



merits have corroborated our earlier ones, which showed that milk is not 

 particularly rich in vitamine B in comparison with many other natural food- 

 stuffs. Neither seasonal variations, differences in the rations fed to the lac- 

 tating cows, nor manipulations of the milk prior to marketing appeared to 

 offer a satisfactory explanation of the differences between our results and 

 those recorded by Hopkins. 



Experiments described in the literature of the vitamines have suggested 

 that egg-3^olk might be an unusually advantageous source for preparing ex- 

 tracts high in their concentration of vitamine B. Preliminary tests which 

 we have made with fat-free concentrates have failed, however, to yield prepa- 

 rations of relatively high potency from this source. It thus appears that 

 the egg yolk, like the milk, is not unusually rich in vitamine B. 



In an earlier paper deaUng with citrus fruits, we stated that preliminary 

 tests indicated that dried orange juice contains some vitamine A. This con- 

 clusion was based on the fact that when the equivalent of 10 c. c. of the juice 

 was furnished daily to rats on a diet practically devoid of vitamine A, the 

 symptoms which should characteristically ensue did not develop within the 

 period of 190 days during which our observations continued. 



A reinvestigation of the subject has substantiated our earlier conclusion. 

 Owing to the comparative richness of orange juice in carbohydrates, so that 

 10 c. c. represent a not inconsiderable intake of nonprotein calories, the pro- 

 portion of protein and essential salts in the ration was made large enough 

 to promote growth at the normal rate. A number of rats maintained on this 

 diet, consisting of casein, starch, lard, and salt mixture, together with 0.2 gram 

 of dried brewery yeast as a source of vitamine B, developed the characteristic 

 ophthalmia associated with a lack of vitamine A and were completely cured 

 within a few days after the daily administration of either 10 c. c. of fresh orange 

 juice, or the same amount of juice admixed with starch and desiccated in a 

 current of hot air. To cure the ophthalmia, 5 c. c. of juice sufficed, but a 

 larger quantity appeared to be necessary to secure restoration of growth. 

 Inasmuch as Cooper has reported the presence of vitamine A in orange peel, 

 special precaution was taken in our work to avoid contamination of the juice 

 with the latter. 



The data now available from animal-feeding experiments indicate the pres- 

 ence of vitamines A, B, and C in the orange and the possibility of conserv- 

 ing them, in part at least, by suitable processes of desiccation. Our experi- 

 ments indicate that, volume for volume, orange juice is as rich as is milk in 

 vitamine B, but somewhat less rich in vitamine A. According to the data 

 furnished by Givens and McClugage, orange juice is much richer than milk 

 in vitamine C. 



Experiments with rats have shown that celery, dandelion, and parsley 

 contain noteworthy amounts of vitamine B. The edible parts of asparagus, 

 celery, and lettuce contain much more vitamine B than do apples, pears, or 

 the juice of grapes. The foregoing evidence serves anew to emphasize the 

 importance of these vegetables in the diet of man. 



It is interesting to note that decoctions of tea leaves, stronger than those 

 ordinarily drunk by man, failed to supply sufficient vitamine B for rats on an 

 otherwise adequate diet, even when 10 c. c. of the decoction, which formed the 

 sole source of water intake, was consumed per day. 



