534 
Bottomley . — The Significance of Certain 
obtained from the phosphotungstic acid fraction amounted to 12*0096 grm., 
and since this was made up for experimental purposes into a solution con- 
taining the fraction from 10 grm. of peat per litre, the proportion of the dry 
phosphotungstic acid fraction in the final solution employed consisted of 
seventeen parts per million. This fraction was tested upon wheat seedlings 
in conjunction with Detmer’s complete food solution. Ten seedlings were 
germinated in clean sand in each of nine pots, which were arranged in 
three series of three pots each. Series I was treated with complete food 
solution, Series II with complete food plus alcoholic extract from 10 grm. 
of peat per litre of solution, and Series III with complete food plus phospho- 
tungstic fraction from 10 grm. of peat per litre of solution. The food 
solution employed contained nitrogen, phosphorus, and potash, estimated 
as NH 3 , P 2 0 5 , and K 2 0 , in the proportion of 400, 200, and 1,220 parts per 
million respectively, so that in addition Series III had seventeen parts 
per million of dry substance obtained from the phosphotungstic fraction. 
Each pot was treated with 100 c.c. of its solution one week after sowing the 
seed, and the treatment repeated once weekly for five weeks, at the end 
of which period the plants were uprooted, washed, dried, and weighed. 
The results were as follows : 
Table I. 
Series. Weight of 30 plants. 
T. Complete food solution 11*94 grm. 
IT. Complete food plus alcoholic extract . . . 14*46 g rm * 
III. Complete food plus phosphotungstic fraction 15*45 grm. 
Increase over 
Series I. 
2 1* i % 
2 9'4 % 
The results thus obtained indicate that the substance in bacterized 
peat which is so effective a stimulant of plant growth is also precipitated 
by phosphotungstic acid, and that this phosphotungstic fraction is quite as 
effective as the original alcoholic extract of the peat. Funk found that 
upon further fractionation of his phosphotungstic acid precipitate with 
silver nitrate and baryta, and elimination of the reagents, he obtained some 
relatively pure crystalline substances to which he gave the name ‘ vitamines ’, 
and these he considered to be the specific curative substances. In order to 
determine how far the growth stimulant in bacterized peat resembled these 
so-called f vitamines ’, a further fractionation was carried out along the lines 
described in his paper. 
The phosphotungstic acid precipitate was decomposed as before 
described with baryta, and the last traces of baryta eliminated by means 
of sulphuric acid. To the filtrate from the barium salt, silver nitrate was 
first added, and then baryta, until no further precipitate was produced. 
The brownish precipitate was filtered off, well washed, suspended in dilute 
sulphuric acid, and decomposed with sulphuretted hydrogen. The filtrate 
from the silver sulphide was then exactly neutralized with baryta, the clear 
