396 



VITAMIN Bi2 



1. Purine and Pyrimidine Desoxyribosides 481 



2. Effect of Reducing Agents 481 



3. Methionine 484 



4. Forms of Vitamin B12 with Greater Potency for Microorganisms 

 than for Animals 485 



5. Antimetabolites of Vitamin B12 487 



XI. Pathology 489 



A. Chicks 489 



A. Rats 490 



C. Human Beings 491 



1. Introduction 491 



2. Mechanisms •:.... 491 



3. Pernicious Anemia 492 



3. Fish Tapeworm Infestation 501 



5. Gastrectomy 502 



6. Intestinal Abnormalities 502 



7. Human Growth Factor 503 



8. Neurologic Disorders 503 



9. Summary 504 



XII. Pharmacology 506 



A. Actions and Uses 506 



B. Dose 506 



C. Toxicity 506 



XIII. Requirements 507 



A. Of Chicks 507 



1. Relationships between Pantothenic Acid and Vitamin B12 in Chicks 512 



B. Of Rats 513 



C. Of Pigs 517 



D. Of Ruminants 521 



E. Of Human Beings 522 



I. Nomenclature and Formulas 



ROBERT S. HARRIS 



Accepted names: 



Obsolete names: 



Empirical formula: 



Chemical name: 



Structural formula: see p. 411 



Vitamin B12 



Cyanocobalamin (B12) 



Hydroxocobalamin (Bi2a and 12b) 



Animal protein factor 



Erythrotin 



Factor X 



Physin 



Zoopherin 



(?) C63H84N14O14PC0 



Not yet determined 



