392 ASCORBIC ACID 



Much of the older work on scurvy should be repeated, using diets presum- 

 ably adequate in all factors other than ascorbic acid. Symptoms on which 

 there is lack of agreement, at least as to degree of development, are swelling 

 of joints, accumulation of water in the body cavity, and marked enlarge- 

 ment of the adrenals. In much of the published work there has been no 

 control of food intake. There is definite need of study of the effect of food 

 restriction, particularly on gastrointestinal hemorrhages. 



b. Relation of the Vitamin to Phagocytic Activity and Fragility 



Further studies should undoubtedly be made in this field under a variety 

 of conditions in an attempt to evaluate quantitatively possible special 

 needs of the vitamin for combating different types of infections. Special 

 attention should be directed to observing if, under conditions of inadequate 

 ascorbic acid supply, the polymorphonuclear cells tend to remain in the 

 circulating blood stream and have a lessened tendency to migrate to the 

 tissues. 



c. Changes in the Circulatory System 



It is obvious that further effort should be made to determine the locali- 

 zation and causes of weakness of the blood vessel walls. How and from where 

 does the hemorrhagic blood escape from the vessels? Can the red cells pass 

 through the dilated capillary walls as do the w^hite cells normally? An 

 observation by Nungester and Ames^^ suggests this possibility, although it 

 is also possible that actual rupture of blood vessels occurs. They found that 

 intraperitoneal exudates from scorbutic animals were invariably contami- 

 nated with large numbers of red blood cells whereas none were found in 

 exudates having vitamin C content above 0.45 mg. per 100 ml. By studying 

 different stages of embryos from animals on scorbutigenic diets, what con- 

 clusions can be reached as to the relation of the vitamin to cell boundaries 

 and intercellular cement of the capillaries? Is the thin-walled condition 

 characteristic of blood vessels in advanced scurvy, particularly of 

 the chronic type, preceded by a somewhat thick-walled condition as a pos- 

 sible consequence of imperfect organization of cell materials? Are the leu- 

 coblasts of scorbutic animals longer lived than those of normal animals? 



d. Mineral Metabolism 



Studies are needed to determine the relation of ascorbic acid to (1) the 

 proportion of ionized to total calcium in the blood, (2) the effect of the 

 level of calcium in the diet on the ascorbic acid requirement and (3) possible 

 changes in the proportion of phosphate to carbonate in teeth and bones 

 after administering the vitamin to scorbutic animals. 



