THE METABOLISM OF VITAMINS 343 



tract this vitamin (McCollum and Simmonds(a), 1918). The addition of 

 a small amount of hydrochloric acid to alcohol increases the efficiency of 

 the extraction and the best results are obtained by using acid methylalcohol 

 (Voegtlin and Myers(d), 1920). If the alcoholic extract is deposited 

 upon dextrin and the mixture dried, the deposited vitamin may be dissolved 

 by benzene, but not by acetone (McCollum and Simmonds(a), 1918). 

 Voegtlin and Myers(d) (1920) showed that olive oil or oleic acid extracts 

 the antineuritic vitamin from autolyzed yeast, thus proving that at least 

 under certain conditions this vitamin is fat-soluble, as well as water-soluble. 

 The great water-solubility of this vitamin suggests that in the cooking of 

 fresh foods in water a considerable amount of this substance may pass 

 into the water, and that the latter should therefore be consumed with the 

 cooked food whenever possible. The active substance diffuses easily 

 through the ordinary semi-permeable membranes (Chamberlain and Ved- 

 der(a) (6), 1911, and Sugiura, 1918), a fact which indicates that the anti- 

 neuritic vitamin very probably has a relatively small molecular weight. 

 It is safe to regard the antineuritic vitamin as it occurs in the natural 

 foods as resistant to drying or moderate heating, up to 100 C. Prolonged 

 heating of foods above 100 C., as used in the process of commercial 

 canning, appears to destroy a variable proportion of this factor (Grijns, 

 1901; Eijkman(e), 1906; Hoist, 1907; McCollum and Davis(rf), 1915). 

 In an alkaline medium destruction proceeds much more rapidly, especially 

 if the temperature is raised to 100 C. (Cooper(a), 1913; Vedder and 

 Williams, 1913; Sullivan and Voegtlm(a), 1916; Steenbock(a), 1917; 

 Drummoiid(a), 1917; Chick and Hume(d), 1919). For example, it was 

 found that cornbread made from low extraction cornmeal, baking soda, 

 salt and water was deficient in antineuritic vitamin, whereas cornbread 

 made without the addition of sodium bicarbonate still contained this vita- 

 min (Voegtlin, Sullivan and Myers, 1916). The use of baking soda in 

 cooking is therefore contraindicated unless proper provisions are made 

 to neutralize the free alkali, as for instance by the addition of buttermilk 

 in bread making. Several observers (Cooper and Funk, 1911; Sullivan 

 and Voegtlin(a), 1916) have noted that the antineuritic substance is highly 

 resistant to acids, as prolonged boiling with 10 p.c. sulphuric or hydro- 

 chloric acid does not seem to lead to any appreciable deterioration ; on the 

 contrary, the physiological activity of crude extracts of foods containing 

 this vitamin was greatly increased by this treatment, as shown by the ' 

 prompt relief of the symptoms in polyneuritic birds (Vedder and Williams, 

 1913; Sullivan and Voegtlin, 1916). 



Zilva (1919) has demonstrated that the antineuritic vitamin in 

 autolyzed yeast is not destroyed when exposed for six hours to ultraviolet 

 rays, nor does radium emanation seem to have any deleterious action upon 

 this substance (Funk(e), 1916). Sugiura and Benedict (1919) claim that 

 the growth-promoting factors in yeast may be partially inactivated by this 



