NUTRITION. 399 



weights of approximately 300 gm. before giving any indication of 

 qualitative inadequacy of their diet. Some of the dried plant products 

 were quite as efficacious in supplying the needed fat-soluble vitamine. 

 This was true for the alfalfa, clover, grasses, spinach, and carrot. 

 Cabbage was less satisfactory in these small quantities, and in the case 

 of potato large amounts were necessary to furnish a quantity of fat- 

 soluble vitamine sufficient to promote growth for even a limited period. 

 The tomato was unique in its efficiency. The latter vegetable has 

 now been demonstrated to furnish all three at present recognized 

 types of vitamine in considerable concentration and to retain its 

 properties even after desiccation. 



Our observations on the occurrence of fat-soluble vitamine in 

 the dried plant-tissues indicate, contrary to the assumption of some 

 investigators, that mild heating and desiccation do not necessarily 

 deteriorate the fat-soluble vitamine in the fresh foods. This now 

 abundantly verified fact is important in connection with the present- 

 day attempts to conserve by desiccation all the essential properties of 

 many natural foods. 



In summarizing our studies of the past year, together with those 

 of other recent investigators, we have remarked that they indicate the 

 richness of many types of plant tissues in those nutritive properties 

 termed vitamines and place the dietary importance of the green vege- 

 tables in an entu'ely new light. They fiu"ther show that the fat-soluble 

 vitamine need not be sought solely in foods known to be rich in fats. 

 The use of vegetables and fruits is thus emphasized, as supplements to 

 the refined products of the modern food industry, which are rich in 

 proteins, fats, and carbohydrates, but in many cases comparatively 

 deficient in the vitamines. 



In the report for 1919 attention was directed to attempts to prepare 

 rations as free as possible from the water-soluble vitamine. We 

 have since directed our efforts to preparing diets free likewise from the 

 fat-soluble vitamine. The results of these still incomplete experi- 

 ments indicate that a preliminary treatment with alcohol and subse- 

 quent long-continued extraction with ether containing both alcohol 

 and water removes the fat-soluble vitamine from proteins, starch, and 

 yeast more completely than does extraction with pure anhydrous ether 

 alone, in so far as one can judge by the time which elapses before grow- 

 ing animals show characteristic failures of growth on diets thus 

 treated. 



There is much to suggest that the fat-soluble vitamine is combined 

 in the tissues in some way analogous to the phosphatide-protein com- 

 pounds which are known to exist and from which the phosphatide is 

 not extracted by ether until it has been liberated by preliminary treat- 

 ment with alcohol. However, our young animals, on diets as free from 

 the fat-soluble \'itamine as we have thus been able to make them, grew 



