/l/ Deficiency signs, when not Irreversible, may be aXlevlated and the animal restored to health by administration of 

 therapeutic doses of the vitamin. /2/ Some causes of deficiency signs, other than dietary deficiency of the vitamin, 

 are: aixy factor ln5)alring digestion or absorption of fat, as inflamnation of Intestinal mucosa, sprue (cf. Folic acid), 

 or chronic diarrhea; excessive Ingestion of mineral oil; hyperthyroidism (inhibits conversion of provitamins to vitamin 

 Ai). /3/ Wide margin of safety between amounts reccomended for normal Intake, prophylaxis, and therapeutic use. 

 /k/ Simulation of deficiency effects makes i^) the syndrcne of scurvy which may vary in extent emd degree with extent of 

 deficiency. 



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