398 CARNEGIE INSTITUTION OF WASHINGTON. 



alfalfa and clover surpassed all the other nine products tested in equal 

 doses of dried material as sole sources of water-soluble vitamine; 

 1 gm. per day promoted far better growth than we have ever secured 

 with even 16 c. c. per day of milk, containing 2 gm. of solids, fed as a 

 source of water-soluble vitamine in addition to the same basal ration; 

 0.5 gm. per day of dry alfalfa or clover is not equally efficient. Tomato 

 is rich in water-soluble vitamine. Even 0.2-gm. quantities occasionally 

 promoted hmited growth. Doses of spinach, cabbage, turnip, and 

 carrot of 1 gm. did not surpass 0.5-gm. quantities of alfalfa and clover 

 in the results attained, whereas with smaller amounts growth was not 

 maintained. The beet root did not equal the other roots tested. The 

 timothy hay, though potent in the earlier periods of the experiments, 

 proved disappointing in the long run. The potato proved to be as 

 rich in water-soluble vitamine as some of the roots tested, although 

 similar quantities of alfalfa, clover, or tomato promoted more rapid 

 growth. Compared in 1-gm. daily doses, there was httle advantage in 

 potato retaining the outer layers over peeled potato of the same age. 

 Dried potato peel was no richer in the vitamine than corresponding 

 quantities of whole potato. Even 2-gm. daily doses of peeled potato 

 did not promote growth at the normal rate. Comparative tests with 

 old and new potatoes have not given indications of any noteworthy 

 differences in content of the water-soluble vitamine. 



Until quite recently the importance of plant tissues as carriers of the 

 fat-soluble vitamine has received little recognition in the study of 

 nutrition. Following the demonstration of the occurrence of this 

 food factor in a number of green foods and other vegetable products, 

 we have made a study of the quantities of these carriers of fat-soluble 

 vitamine which serve to keep growing rats in health and vigor when all 

 the other known essential food-factors are supplied. On the basal 

 food mixture employed by us, rats fail to grow after about 40 to 80 days 

 and then begin to decline rapidly in bodj^-weight. Under such cir- 

 cumstances, unless the physiological damage has proceeded too far, 

 restoration of growth and well-being is usually readily brought about 

 by inclusion of butter-fat in place of part of the lard in the food mixture. 

 The characteristic eye conditions or sjrmptoms, sometimes termed 

 xerophthalmia, or perhaps better keratomalacia, which often develop 

 during the decline in health, are speedily relieved when the nutritive 

 conditions begin to improve. 



The various plant products dried at a comparatively low tempera- 

 ture were fed as sources of fat-soluble vitamine apart from the food 

 mixture in daily doses of approximately 0.1 gm. of dried substance. 

 For comparison, a group of animals daily received 0.1 gm. of butter-fat, 

 as this product has been already demonstrated to be especially rich 

 in the fat-soluble vitamine. With this comparatively small intake of 

 the latter, the animals receiving the butter-fat reached maximum 



