ORGANIC MATTERS OF THE SOIL. 237 
(such as ink) which cannot nourish the plant. The latter 
(ink, etc.) leave evidences of their entrance into the plant, 
while the former are changed and partly assimilated. 
“A bean 15 inches high, whose roots were placed in a 
decoction of Brazil-wood (to which a little alum had been 
added and which was filtered), was able to absorb no more 
than the fifth part of its weight of this solution without 
wilting and dying. In this process four-fifths of its stem 
was colored red. 
“Polygonum Persicaria (on occasion an aquatic or bog 
plant) grew very well in the same solution and absorbed 
its coloring matter, but the color never reached the stem. 
The red principle of Brazil-wood being partially assimilat- 
ed by the Polygonum, underwent a chemical change; 
while in the bean, which it was unable to nourish, it suf: 
fered no change. The Polygonum itself became colored, 
and withered when its roots were immersed in diluted 
ink.” 
Biot (Comptes Rendus, 1837, 1, 12) observed that the 
red juice of Phytolacca decandra (poke-weed), when 
poured upon the soil in which a white hyacinth was blos- 
soming, was absorbed by the plant, and in one to two 
hours dyed the flowers of its own color. After two or 
three days, however, the red color disappeared, the flow- 
ers becoming white again. 
From the facts just detailed, we conclude that some 
kinds of organic matters may be absorbed and chemically 
changed (certain of them assimilated) by agricultural 
plants. 
We must therefore hold it to be extremely probable 
that various forms of humus, viz., soluble humates, ulmates, 
crenates, and apocrenates, together with the other soluble 
organic matters of the soil, are taken up by plants, and 
decomposed or transformed, nay, we may say, assimilated 
by them. 
