July 24, 1916 Properties of the Virus of Mosaic Disease 



653 



were made up to an alcoholic strength of 80 per cent with absolute alcohol. 

 This solution was prepared on November 6, 191 5, and allowed to stand 

 until November 8, when the precipitate was collected by filtration and 

 evaporated to dryness at room temperatures. . This residue was taken up 

 with 100 c. c. of distilled water. The original filtrate was also tested for 

 peroxidase and likewise by inoculation. 



Since earlier experiments have shown that the infective principle is 

 not destroyed in alcoholic strengths of 45 to 50 per cent for several days, 

 precipitation tests were also made with these strengths. Of virus X 20 , 

 used in the preceding test, 160 c. c. were made up to a 50 per cent alcoholic 

 solution with absolute alcohol on November 6, 191 5. A portion of the 

 supernatant, clear solution was then siphoned off very carefully without 

 disturbing the heavy, flocculent precipitate below. The precipitate was 

 then collected on filter paper and freed from alcohol at room tempera- 

 tures on November 8 to November 10. This residue was then taken up 

 with 100 c. c. of distilled water (Table IV). 



Table IV. — Infectivity of mosaic virus after having been precipitated in 75, 80, 50, 

 and 45 per cent alcoholic solutions 



