1922] RUDOLFS—SEEDS 217 
definite time intervals, during which the seeds remained in contact 
with the solutions. Each of the data given represents the average 
of the results obtained from two or more trials made with the same 
number of seeds soaked in equal amounts of solution for time 
periods of the same duration. 
From the data of table I it will be observed that in all cases the 
- H-ion concentrations of the solutions were markedly increased by 
contact with the seeds, even when strongly alkaline solutions of 
potassium carbonate were used. ‘The seeds immersed in solutions 
of different concentrations of a single salt had a tendency to bring 
the P, values of the solutions to a point which was fairly constant 
for a given species of seed, regardless of the original salt concentra- 
tion or of the initial P, values of the solutions, except when the 
- solutions .were very dilute. The maximum reaction change pro- 
duced by corn in the various concentrations of all the salts used, 
except potassium carbonate, brought the final P, values of the 
solutions to approximately 4.1, varying only slightly above or below 
this value except in the very dilute solutions (0.01 and 0.001 atm.) 
as previously noted. While the final P, values produced by the 
seeds of other species were approximately constant in the different 
concentrations of the same salt, they varied considerably in the 
solutions of the different salts. For example, the final P, values 
produced by wheat in the magnesium sulphate solutions were 
around 4.9, in the potassium chloride solutions they were approxi- 
mately 5.7. Watermelon seeds produced corresponding P, values 
of approximately 5.0 in the magnesium sulphate solutions and 4.1 in 
calcium nitrate solutions. Seeds of other species produced similar 
differences in the P, values of the solutions of the different salts. 
It will be observed that the initial H-ion concentration of the 
solutions of each salt increased slightly with the progressive decrease 
in the total salt concentration, but the P, values of the solutions 
after soaking the seeds in them for fifteen hours showed a striking 
similarity in value, except in the very dilute solutions. With a 
few exceptions the seeds were incapable of bringing about any 
marked reaction changes in the very dilute solutions (0.01-0.001 
atm.), behaving in these solutions in somewhat the same manner 
with respect to changes in reaction as they did in distilled water. 
