ISH COMPOSTITA. 
ing a singular tingling sensation, anda remarkable flow of - 
saliva. The drug is very liable to the attacks of insects. 
Microscopic structwre.x—The cortical part of this root is re- 
markable on account of its suberous layer, which is partly 
made up of sclerenchyme (thick-walled cells). Balsam-ducts. 
(oil cells) occur as well in the middle cortical layer as in the 
medullary rays. Most of the parenchymatous cells are loaded 
with inulin; pellitory, in fact, is one of those roots most 
abounding in that substance. 
Chemical composition.—Pellitory was first analysed by Pari-: 
sel, who gave the name Pyrethrin to a soft resin soluble in 
alcoholand ether. Koene subsequently found in the roota resin, 
brown acrid oil, yellow oil, inulin, gum, salts and a trace of 
tannin. The two oils and resin together were said to con- 
stitute the pyrethrin of Parisel, and the active principle has 
consequently been regarded as a mixed substance. C.J. 8. 
Thompson (Pharm. Journ. [8], xvii. 567,) finds the active 
principle to be an acrid resinous substance, residing mostly 
_ in the cortical portion, and occurring to the extent of 5 per 
cent, in good samples of root. Avery minute quantity placed 
on the tongue causes a strong burning sensation, which 
shortly -inereases, and remains for a oousifiarable time, 
inducing a copious flow of saliva. A strong solution painted on 
the skin causes a sharp prickling sensation, and reddens 
the part where it has been applied. If the part is kept 
covered a blister will be produced. Besides being soluble 
in ‘alcohol and ether, it dissolves in oils and acetic acid. It is 
‘composed of an acrid, brown resinous substance soluble in 
alcohol, but insoluble in water and strong alkaline solutions; and 
a dark yellow oil which is soluble in alkalies. The acridity of 
the oil is probably due to a small quantity of resin mixed with it. 
‘R. Buchheim has recently claimed to have found the active 
principle to be a crystalline alkaloid, Pyrethrine, which he 
obtained by evaporating to dryness an alcoholic extract and 
exhausting the residue with ether. Pyrethrine melts at the 
heat of the body, and is resol 
cholic potash into 
by ale pipe- 
ridine and pyrethric acid, (Arch. f Ex aperim. Path. 5., p. 458.) -— a 
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