lz TOXIC SUBSTANCE EXCRETED BY PLANTS. 
The data given in the table prove that all the plants tried, 
wither in the same order in the different solutions; thus all do 
worst in the ‘gram water,’ ‘‘sesamum water” being the next 
most toxic, followed in order by wheat, cotton, cajanus, sorghum. 
This order could of course be easily changed by diluting any 
one or more of the solutions, the strengths of which in the 
experiment are quite arbitrary. 
The fact of this regularity appears to favour the view put 
forward above that the substances excreted by various plants are 
dentical, and that the solutions used differ only in concentration 
and not in kind. 
Nature of the Toxic Substance. 
It was at first thought that the toxic matter might be an 
albumose or similar substance. The solutions, however, all gave 
negative results, on the application of the biuret and other tests 
for these compounds. 
The fact that tannic acid precipitated and corrected the 
toxic material suggested the presence of an alkaloid. 
It is interesting to note that leaves containing tannic acid 
are systematically used as manure in the spice gardens and rice 
fields of Canara* and that the cultivators’ opinion as to the manu- 
rial value of the leaves of any particular variety of tree corres- 
ponds apparently to the amount of tannic acid contained in 
the leaf. Thus in the order of preference the leaves of the 
following trees (among others) are utilized in this way :— 
Hirda (Terminalia chebula). 
Matti ( Do. tomentosa). 
Honal (Do. paniculata), 
Kanagal (Dillenia pentagyna). 
That it is not the ash constituents of these leaves that produce 
the manurial effect is obvious from the fact that if the leaves be 
burnt and the ashes Beppee to ot ba ot the spices to 
m Mollisoh—" Caliieeiion of Betel, Palm, Cardamom and Pepper in the Kanara District 
of the Bombay Presidency” (Bulletin No. 20 of the Department of Land Records and 
Agriculture, Bombay, 1900). 
