VITAMIN B (Si) 57 



only essential complex in the extracts described." (These experiments 

 probably deal with Bi, in the present sense of the term.) A few experi- 

 ments on the stability toward acids and alkalies of water-soluble B 

 in the form of an alcohol solution of wheat embryo were also reported. 

 These tended to confirm similar tests of the antineuritic vitamin in its 

 rapid destruction by alkalies and relatively marked stability toward 

 hydrochloric acid. Nitrous acid had slight if any action, this fact con- 

 stituting a strong indication that the active substance is neither a pri- 

 mary nor a secondary amine. 



Osborne and Wakeman (1919) in an attempt to obtain from yeast 

 a concentrate of vitamin B relatively free from proteins and related 

 substances first coagulated the protein by boiling water, thus removing 

 all but a comparatively small proportion of the total solids of the yeast, 

 and then subjected the water extract to fractional precipitation v^th 

 alcohol. The preliminary treatment of the yeast, which was later adopted 

 by Seidell and others in their attempts to isolate the antineuritic vitamin, 

 was described as follows: "Several liters of fresh bottom yeast were 

 obtained directly from a brewery, and immediately diluted with ice 

 water. After centrifuging, the sediment was washed twice more in 

 the same way. The moist, washed yeast weighed 264 grams, equal to 

 48 grams dried at 107° C. This was stirred gradually into 1 liter of 

 boiling distilled water containing 10 cubic centimeters of 1 per cent 

 acetic acid. After boiling for about 2 minutes the solids were sepa- 

 rated from the extract with the centrifuge. The residue was washed 

 once by boiling with 0.01 per cent acetic acid and, after centrifuging, 

 the extracts were united and concentrated to 500 cubic centimeters. 

 This concentrated extract contained 8.14 grams of solids, equal to 17.1 

 per cent of dry yeast, and 0.666 gram of nitrogen, equal to 14.4 

 per cent of the original yeast nitrogen or to 8.18 per cent of the solids 

 of the extract." 



This concentrate although containing less than one-fifth of the 

 solids and only one-seventh of the nitrogen of the yeast contained 

 nearly all of the vitamin B as then understood. Daily doses of 17 milli- 

 grams of the solids of the extract, equivalent to 0.1 gram of the original 

 dried yeast, sufficed to bring about the recovery and rapid growth of 

 young rats declining on a diet free from the water-soluble vitamin. 

 By treating the extract successively with alcohol to 52, 79, and 90 per 

 cent concentration by weight, three flocculent precipitates were ob- 

 tained, all of which contained some of the vitamins. Fraction II, how- 

 ever, contained by far the greater part. This fraction, after washing 

 with 79 per cent alcohol, twice dissolving in 100 cubic centimeters of 



