F. FLETCHER. 1s: 
which the leaf manure is applied—the pepper vine is killed. 
Similarly neither irrigation nor farm-yard manure serves the 
purpose of the leaves; the latter therefore serves neither for 
storage and regulation of water nor as a supply of nitrogen. 
It was indeed these facts that first suggested to me the possi- 
bility of the toxic substance being either an albuminous substance 
or an alkaloid for both of which tannic acid acts as a precipitant. 
A. preliminary examination of the solutions only has been as 
yet made, but this appears to prove that it is an alkaloid that 
is excreted by all the plants experimented with, and further that 
the substance is identical in all cases. 
The solutions examined consisted of both well and distilled 
water in which plants had grown. 
The principal reactions obtained are as follows :— 
Phosphomolybdic acid ae ... A white precipitate. 
Phosphotungstic acid te see Do. do. 
Mayer’s Reagent ene < Do. do. 
Tannic acid ee BE Do. do. 
Platinum chloride oe 
: ams, 5 ; Precipitates on standing. 
Todised potassium iodide 
Mercurie chloride ty . A coagulated white precipitate. 
The sabtance is thrown down in concentrated solutions only 
as a white flocculent precipitate on adding caustic potash. A 
similar precipitate is thrown down immediately on adding potas- 
sium nitrate, potassium chloride, potassium sulphate or sodium 
chloride and after some time on adding sodium nitrate or sul- 
phate. Potassium chloride and sulphate and sodium chloride 
produce coagulated precipitates and apparently precipitate the 
substance most completely of the reagents tried. The precipi- 
tate is insoluble in water, alcohol and all the usual organic solvents, 
but soluble in acids and alkalies. This precipitate can be titrated 
with an acid using methyl orange as indicator. It is there- 
fore apparently the base itself and not a salt. The salt formed 
on titration is acid to litmus as is also distilled water in which 
plants have grown. This fact apparently accounts for statements 
that free acids or acid salts are exuded by plant roots. Further, on 
precipitation the solution becomes distinctly acid to methyl orange. 
