VITAMIN C 215 



The concentrate as thus prepared, when diluted to the original 

 volume contained from 0.03 to 0.05 per cent of total solids and was 

 capable of preventing scurvy in guinea pigs in doses as low as 1.5 

 cubic centimeter daily. It reduced ammoniacal silver nitrate in the cold 

 and decolorized potassium permanganate. 



In spite of the close association of reducing and antiscorbutic prop- 

 erties, Connell and Zilva (1924) found that destruction of vitamin C 

 and of reducing properties did not proceed at the same rate. The ma- 

 terial responsible for the decolorization of potassium permanganate 

 was very little affected by heat or alkalinity. The ability to reduce 

 ammoniacal silver nitrate was somewhat decreased, but in much less 

 degree than the inactivation of antiscorbutic properties. It was con- 

 cluded that a part at least of the reducing material in vitamin C concen- 

 trates is chemically independent of the vitamin itself. 



Bezssonoff (1925) also made use of basic lead acetate as a precipi- 

 tant of vitamin C. He had earlier (1921) used neutral lead acetate 

 to remove some of the inactive material from cabbage juice, concen- 

 trating the filtrate, after removal of the lead, to a hygroscopic yellowish 

 white powder which was said to furnish sufficient vitamin C for 600 

 gram guinea pigs in 0.1 gram doses. 



In the modified method, 100 liters of fresh cabbage juice was treated with 

 40 liters of water containing 320 grams of lead acetate and 1,600 cubic centimeters 

 of acetic acid. The fiUrate, without being freed from lead, was brought to pH 8.2 

 with sodium hydroxide with the formation of a precipitate containing the active 

 material. This was dissolved in acetic acid and the process repeated twice. The 

 final precipitate was dissolved in acetic acid and treated with hydrogen sulfide 

 under pressure to precipitate the lead. The filtrate was subjected to four evapora- 

 tions in vacuo at 25° C. with subsequent dilution with distilled water and finally 

 extracted successively with absolute alcohol and acetone. 



The extract as thus prepared yielded on evaporation colorless 

 needle-like crystals which were very hygroscopic and easily oxidized, 

 "forming a yellowish brown quinone." The oxidation product, but not 

 the original crystals, gave the blue color reaction considered by 

 Bezssonoff (1921b, 1923a) to be characteristic of vitamin C. Two 

 cryoscopic determinations of the molecular weight of the crystalline 

 substance gave values of 200 and 230. It melted at 47° C. and con- 

 tained 45.57 per cent carbon, 48.24 per cent oxygen and 6.19 per cent 

 hydrogen. It was soluble in water in all proportions and insoluble in 

 ether, benzene, and toluene. The minimum protective dose for guinea 

 pigs was less than 2 milligrams daily. 



In view of the elementary analysis reported by Bezssonoff for his 

 most active vitamin C concentrate, it is of interest that Zilva (1925a) 

 reported at about the same time that his vitamin C concentrates always 



