466 HUMULUS LUPULUS. 
to show that this portion may effectually super- 
cede all the rest, in common practical use. 
This substance, when separated from the hops 
by rubbing and sifting, exists in the form of a 
fine yellow powder. It is adhesive when rubbed 
between the fingers, and becomes agglutinated 
by moderate heat. It is very inflammable, and 
burns entirely out with a white flame, leaving a 
light cinder. irpaa 
- Dr. Ives has made a variety of experiments 
with this powder, from which he concludes that 
it consists of tannin, extractive matter, a bitter 
principle, wax, resin, and a woody fibrous sub- 
stance; besides the aromatic principle, which he 
was unable to separate in the form of volatile oil. 
It may be observed, that the powder, as employed 
by him, being obtained from the hops by agitation 
and’ sifting, must necessarily contain a certain: 
- portion of chaff or minute fragments of the scales ; 
and that these are apparently the seat of the tan- 
nin, the woody insoluble substance, and possibly 
of some other ingredients. If the pure secretion 
be carefully separated from the scales by brush- 
ing, and dissolved in alcohol, it does not undergo 
any change of colour from the sulphate of iron ; 
although the scales themselves, as well as the 
