244 



Prof. W. B. Bottomley. 



and Series III with the complete food solution +0 - 35 part per million of the 

 silver fraction. The pots were first treated one week after sowing the seed, 

 and after that each pot received once weekly 100 c.c. of its food solution for 

 seven weeks. At the end of that period the plants were washed, dried, and 

 weighed, and, after the gross weight had been taken, the plants were all 

 dried in the steam oven at 100° C. until their weight was constant. The 

 results are as follows : — 



Table V. 



Series. 



Gross weight, 

 45 plants. 



Increase over 

 Series I. 



Dry 



weight. 



Increase 

 over I. 







grm. 



per cent. 



grm. 



per cent. 



I. 



Complete food 



64 -5 





13 -3480 





II. 



„ „ + phosphotungstic 



96 -8 



50 -0 



16 -3818 



22 -7 





fraction 











III. 



,, „ + silver fraction ... 



96 -5 



49-6 



15 -7148 



17-7 



The silver fraction from the bacterised peat extract, corresponding with 

 the " vitamine " fraction of Funk, having thus given results approaching 

 those of the phosphotungstic fraction, a preliminary investigation was made 

 to test its effect on the growth of wheat seedlings in water culture. Two 

 sets, each consisting of 18 similar seedlings, were carefully selected, each set 

 being originally of equal weight, viz., 4 - 73 grm. Each set was divided for 

 purposes of water culture among three similar bottles of 200 c.c. capacity, 

 six plants being inserted through notches in the corks of each bottle, so 

 that the roots dipped into the culture solution. The three bottles of set I 

 were filled with a nutrient solution of pure salts in physiologically pure 

 distilled water, in which the proportions of NH 3 , P 2 5 and K 2 were 400, 

 200, and 1220 parts per million respectively ; while those of set II con- 

 tained a precisely similar solution which had received, in addition, - 35 

 part per million of the silver fraction of bacterised peat extract. The 

 bottles were aerated daily, and the solutions changed twice a week, while 

 at the end of every 16 or 17 days the plants were taken from the jars, 

 moisture removed from their roots by means of blotting paper, and weighed. 

 The results obtained are shown in Table VI. 



The change brought about by the addition of the silver fraction is 

 represented by the accompanying curves, in which the dotted line 

 represents the change in weight of the series in pure food, while the 

 unbroken line shows the progressive increase in weight obtained upon the 

 addition of this substance. 



