42 
Tropic acid (the acid of atropine) is phen^dhydracrylic acid 
Scopolamine (hyoscine) is formed b}" the 
union of tropic acid with scopoline, a compound similar to tropine. 
Properties.— Small, colorless, odorless, rhombic crystals or crystal- 
line powder, having a bitter taste. Soluble in 5.7 parts of water and 
32.5 parts of alcohol. It should be kept in well-stoppered vials pro- 
tected from light. 
. Dose. — ‘‘Average dose: 0.0005 Gm. = 0.5 milligramme (yjg grain).” 
(U. S. P.) 
The ph 3 "siological action of homatropine is similar to that of atro- 
pine, but it is less poisonous. The m}"driatic effects of homatropine : 
appear more quickl}^ and pass off‘ in a shorter time than do those of I 
atropine. 
The hydrochloride, sulphate, and salic}date of homatropine have ; 
been used, but the}" seem to have no advantage over the hydrobromide. ! 
Eiqyldlialmin is a recently introduced mydriatic, having a physio- ^ 
logical action very similar to homatropine; it is a mandelic acid deriv- 
ative of heta-eucaine. 
HYDRASTINA. 
Hyd rastiiie. 
CnIbiNOe 
An alkaloid obtained from Hydrastis. The U. S. Pharmacopoeia, 
Eighth Decennial Kevision, demands that Hydrastis contain not 
less than 2.5 per cent of Hydrastine. Hydrastis contains also the 
alkaloids berberine to the extent of 3.5 to 5 per cent, and canadine, 
but its physiological action is due largely to the Hydrastine. Hydras- 
tine is frequently called in commerce the “white alkaloid of hydrastis.” 
The alkaloid hydrastinine (the hydrochloride of which is official) is 
obtained from Hydrastine by the action of oxidizing agents. The 
alkaloid Hydrastine should not be confused with the mixture of 
hydrastine, berberine, etc. , sold under the same name. 
Properties. — “ White, to creamy white, glistening prisms, sometimes 
of large size, possessing a bitter taste, and permanent in the air.” , 
Almost insoluble in water; soluble in 135 parts of alcohol. |j 
“If a crystal of Hydrastine be dissolved in diluted sulphuric acid 
and a solution of potassium permanganate (1 in 10) be added, a blue ' 
fluorescence will be developed (distinction from hydrastinine).” 
Dose. — “Average dose: 0.010 Gm. = 10 milligrammes Q grain).” i 
(U. S. P.) 
Hydrastine is extensively used in preparing the so-called “color- ' 
less hydrastis,” which is a solution of the alkaloid, in a mixture of 
water and glycerin, with the aid of hydrochloric or sulphuric acid. 
