20 THE BIOCHEMISTRY OF B VITAMINS 



best of our knowledge, in representative members of the groups repre- 

 sented by Protozoa, Bacteria and Yeasts. Other examples to be cited later 

 indicate that widespread occurrence in several phyla is not equivalent to 

 universal biological occurrence. 



It was not apparent at the time, but the root name, pantothen-, could 

 have been given appropriately to any member of the B vitamin family 

 because microbiological evidence now reveals that each one is universally 

 present in the same sense that pantothenic acid is. 



The most extensive and systematic study of the distribution of the B 

 vitamins was undertaken in the writer's laboratories. This series of ex- 

 plorations was carried with the full realization that data would be subject 

 to later revision because of improvements in microbiological methods, but 

 they served to demonstrate, as had not been done before, that thiamine, 

 riboflavin, nicotinic acid, pantothenic acid, pyridoxine (pyridoxal, see 

 p. 8), biotin, folic acid and inositol are to be found in any type of 

 biological material that is examined. 



In one study 12 the autolyzates of 50 animal tissues (rat, mouse, beef 

 and swine) were found to contain substantial amounts of every member 

 of the group. Embryonic, immature and mature livers, hearts and brains 

 of rats and chickens were also assayed. 13 In other studies enzymatic 

 digests of seven representative rat tissues, 14 seventeen representative 

 human tissues (three individuals), 15 twenty-three human cancers, 18 

 mouse and rat cancers, 16 cell nuclei from heart and cancer tissues 17 were 

 assayed, always with the same result: substantial amounts of all the 

 substances in question were found. More comprehensive exploration, 18 

 including thirty-four representative materials from eight different biologi- 

 cal phyla (Chordata, Arthropoda, Mollusca, Annelida, Protozoa, Bacteria, 

 Fungi, and Spermatophytes) showed again the universal presence of all 

 eight substances, as had earlier been shown for pantothenic acid. In an- 

 other study, 19 milk from six species (human, mare, cow, goat, dog, mouse) 

 was assayed and all eight substances found in every sample. 



Numerous scattered studies have contributed information and have 

 tended to corroborate the universal occurrence of the B vitamins. The 

 most comprehensive recent compilations of data with respect to their 

 quantitative distribution in foods are cited in the bibliography. 20, 21, 22, 23 

 Due allowances must be made in every case for the shortcomings of the 

 methods used. 



Contrast Between the Distribution of B Vitamins and that of Other 

 Vitamins 



In view of the possible importance of distribution as a criterion for 

 determining whether or not a substance should be classified as a B vita- 



