ACCESSORY FOOD BODIES 105 



efficiency in stimulating plant growth, was also 

 precipitated by Phosphotungstic acid, and that the 

 Phosphotungstic acid fraction was quite as effective 

 as the original alcoholic extract of the peat. Further, 

 some confirmation was given to the hypothesis that 

 the peat contained bodies similar in action to 

 vitamines. 



Funk found that on treating his Phosphotungstic 

 acid fraction with Silver nitrate he had been able to 

 obtain his vitamines in crystalline form. To deter- 

 mine, therefore, how far the growth stimulant in 

 bacterized peat resembled the vitamines, the Phos- 

 photungstic acid fraction of the peat was treated 

 similarly. It was decomposed as described above 

 with Baryta, and to the filtrate from the Barium 

 salt Silver nitrate was added until no further pre- 

 cipitate was produced. The brownish precipitate 

 was filtered off, well washed, suspended in dilute 

 Sulphuric acid, and decomposed with Sulphuretted 

 hydrogen. The nitrate from the Silver sulphide 

 was then exactly neutralized with Baryta, the clear 

 liquid filtered off from the precipitate of Barium 

 sulphate, and evaporated to dryness in vacuo. The 

 weight of dry substance obtained from the Silver 

 fraction from 7 kilogrammes of bacterized peat 

 amounted to 0-2452 gramme, and as this also was 

 made up into a solution so that a litre of it should 

 contain the silver fraction from 10 grammes of 

 peat, the solution contained the Silver fraction to 

 the amount of 0-35 part per 1,000,000 i.e., approxi- 

 mately i part per 3,000,000. 



To test the efficiency of this Silver extract three 



