CHAPTER IX 



DISTRIBUTION, PROPERTIES, AND 

 CHEMISTRY OF THE VITAMIN E GROUP 



1. Introduction 



The fact that additional members of the group of fat-sohible vitamins 

 exist was not recognized until considerable information had already been 

 collected about vitamins A and D. The first suggestion that another fat- 

 soluble vitamin may occur came from the work of Evans and Bishop^ ~^ in 

 1922 and 1923. These investigators found that rats failed to reproduce 

 when fed a purified diet containing adequate amounts of both vitamins A 

 and D and of the other foodstuffs then recognized as required. This de- 

 ficiency could be overcome if an extract containing the missing essential 

 factor was added. It was believed to be a vitamin, and was named 

 "vitamine E." 



Confirmation of the existence of this new fat-soluble vitamin came from 

 many quarters. The biological activity was also found to be much more 

 far-reaching than was originally realized. Mattill and his associates,^ as 

 well as Mattill alone, ^ reported the development of a type of sterility in 

 male rats deprived of a dietary "X substance"; the deficiency was slower 

 in appearing in male rats than it was in female animals, but the testicular 

 damage was found by Mason to be permanent. ^"-^^ It is also not entirely 

 certain whether or not Mattill and Conklin^^ should be given the credit for 

 the discovery of vitamin E, since as early as 1920 these workers reported 

 that disturbances in reproduction occurred in rats fed milk diets. 



Evans and Burr^^ found that weanling rats whose mothers were on re- 

 stricted diets, presumably lacking in vitamin E, developed paralysis; this 



1 H. M. Evans and K. S. Bishop, Science, 56, 650-651 (1922). 



2 H. M. Evans and K. S. Bishop, Am. J. Physiol, 63, 396-397 (1922). 



3 H. M. Evans and K. S. Bishop, /. Am. Med. Assoc, 81, 889-892 (1923). 

 < H. M. Evans and K. S. Bishoj), /. Metabolic Research, 1, 319-333 (1922). 



5 H. M. Evans and K. S. Bishop, J. Metabolic Research, 1, 335-356 (1922). 



6 H. M. Evans and K. S. Bishop, /. Metabolic Research, 3, 201-231 (1923). 

 ' H. M. Evans and K. S. Bishop, /. Metabolic Research, 3, 233-316 (1923). 



« H. A. Mattill, J. S. Caiman, and M. M. Clayton, J. Biol. Chem., 61, 729-740 (1924). 



9 H. A. Mattill, Am. J. Phi/sioL, 79, 305-315 (1927). 



i» K. E. Mason, Proc. Natl. Acad. Sci. U. S., 11, 377-382 (1925). 



" K. E. Mason, J. Exptl. ZooL, 43, 159-229 (1926). 



12 H. A. Mattill and R. E. Conklin, J. Biol. Chem., 44, 137-158 (1920). 



13 H. M. Evans and G. 0. Burr, J. Biol. Chem., 76, 273-297 (1928). 



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