674 



SUBJECT INDEX 



Trypanosoma lewisi, 



biotin and, 611-613 

 Trypsin, 398, 529, 556 



in vitamin B12 assay, 471 

 Tryptophan, 280, 430, 435 

 Tube assays, 



for vitamin Bi2 , 457-466 

 Tumors, 



biotin and, 609-611 



desthiobiotin and, 567 



vitamin B12 in, 443 

 Turkeys, 



vitamin A requirements of, 170 

 Tween 20, 



in biotin replacement, 565 

 Tween 80, 



in biotin replacement, 565 



in growth of Lactobacillus, 456, 458, 459 

 Tyrosinase, 226 



Tyrosine, 227, 280, 306, 330, 364, 367, 374, 

 378, 387, 430 



ascorbic acid and, 236-238 



oxidation of, 313-315, 331, 333-334 



in pernicious anemia, 498 



vitamin B12 and, 425 

 "Tyrosyl derivatives," 



in diagnosis of scurvy, 364-365 



U 



Uracil, 497 



relation to vitamin B12 , 446 

 Uranium nitrate, 248 

 Urea, 



biotin and, 580 



in vitamin B12 deficiency, 421-422 

 Urease, 



ascorbic acid and, 238-239 

 7-(3,4-Ureylenecyclohexyl)butyric acid, 



as biotin inhibitor, 578 

 Ureylenephenyl compounds, 



as biotin inhibitors, 570-571 

 Uridylic acid, 



in vitamin B12 assay, 463 

 Urobilinogen, 370, 378 



in scurv}', 365 

 Uterus, 299 



Vegetables, 

 ascorbic acid assay of, 244 



provitamin A assay of, 93-95 

 vitamin B12 content of, 477 

 Veins, 



in scurvy, 289 

 Virus disease, 



ascorbic acid and, 342-343 

 "Visual white," 59 

 "Visual yellow," 59 

 Vitamin A, 26, 300, 353 

 absorption of, 171, 174 

 absorption spectrum of, 30 

 ascorbic acid and, 222-223, 324-327, 393 

 biochemical functions of, 59-87 

 biological activity of, 55-58 

 chemistry of, 4-58 

 conversion factor, 100 

 conversion to retinene, 63-64 

 deficiency, 



clinicopathologic studies, 139-140 



effect on epithelial tissues, 107-116, 

 147-149, 157-159 



general considerations, 106-107 



in humans, 137-162 



in nutrition survejs, 139 



macroscopic cutaneous lesions in, 

 149-157 



prenatal effects, 135-136 



"primary", 137 



repair of, 113-114 



"secondary," 137 

 definition of unit, 99, 171 

 effect in tissue cultures, 133 

 esterification of, 71, 84 

 estimation, 87-99 



biological, 97-99 



sources of error in, 90-91 



spectrophotometric, 89 

 formation from carotene, 24-25 

 general metabolism of, 82-87 

 industrial preparation of, 41-43 

 in liver oils, 103 

 nomenclature, 3 

 occurrence, 100-106 

 oxidation of, 70 

 properties of, 28-32, 100 

 requirement, 



factors influencing, 174-175 



of animals, 163-170 



of humans, 171-175 

 in rhodopsin synthesis, 46, 72-75, 76-78 

 separation, 92, 96 



i 



