chemically; the bark and wood of the root and the base and
blades of the leaves. Fixed oils were separated from each part. These
were not identical; two were fluid at ordinary temperature, and two
were solid. Their melting and solidifying points were not the same.

This difference in the physical character and chemical reaction of
these fixed oils may be due to the presence of free fatty acid and
glycerides in varying proportions in the four parts of the plants. It
is of interest to note that, in the subterranean part of the _Yucca_,
the oil extracted from the bark is solid at the ordinary temperature;
from the wood it was of a less solid consistency; while the yellow
base of the leaf contained an oil quite soft, and in the green leaf
the oil is almost fluid.

Two new resins were extracted from the yellow and green parts of the
leaf. It was proposed to name them _yuccal_ and _pyrophaeal_ An
examination of the contents of each extract showed a different
quantitative and qualitative result.

Saponin was found in all parts of the plant.

Many of the above facts have been collected from the investigations of
others. I have introduced these statements, selected from a mass of
material, as evidences in favor of the view stated at the beginning of
this paper.[41] My own study has been directed toward the discovery of
saponin in those plants where it was presumably to be found. The
practical use of this theory in plant analysis will lead the chemists
at once to a search for those compounds which morphology shows are
probably present.

I have discovered saponin in all parts of the _Yucca angustifolia_, in
the _Y. filimentosa_ and _Y. gloriosa_, in several species of agavae,
and in plants belonging to the leguminosae family.

The list[42] of plants in which saponin has been discovered is given
in the note. All these plants are contained in the middle plane of
Heckel's scheme. No plants containing saponin have been found among
apetalous groups. No plants have been found containing saponin among
the lower monocotyledons.

The plane of saponin passes from the liliaceae and allied groups to the
rosales and higher dicotyledons.

Saponin belongs to a class of substances called glucosides. Under the
action of dilute acids, it is split up into two substances, glucose
and sopogenin. The chemical nature of this substance is not thoroughly
understood. The commercial[43] product is probably a mixture of
several substances.

This