There was no starchy matter present in the portion examined.
The mode of deciding upon the value or goodness of different samples of scammony, by ascertaining the amount of matter soluble in sulphuric ether, has seemed to me productive of a negative result in showing {9} how much non-resinous matter was present, rather than a certain method of ascertaining the actual amount of scammony resin present; but some experiments upon the resinous residuum lead to a more favorable conclusion.
The results of the analyses made by Johnston, who seems to be the only chemist who has paid any attention to its ultimate composition, show that it varies in composition materially from many other resins.
| According to his analyses, as contained in Löwig, it has the formula | C40 H33 O8 |
| While that of Guaiac resin is | C40 H23 O10 |
| Of Colophony | C40 H30 O4 |
Or expressed in per cents:—
| Scammony. | Guaiac. | Colophony. | |
|---|---|---|---|
| Carbon | 56.08 | 70.37 | 79.81 |
| Hydrogen | 7.93 | 6.60 | 9.77 |
| Oxygen | 35.99 | 23.03 | 10.42 |
| 100.00 | 100.00 | 100.00 |
The resin analysed by Johnston was obtained by evaporating the alcoholic solution, and he describes it as opaque, pale yellow, hard, and brittle; when obtained, however, by evaporating the ethereal solution I have found it transparent.
It might be inferred that, with a composition so different from that of the substances above adduced, its behavior with re-agents would be different from theirs; and its action with strong acids confirms the supposition, as may be seen by reference to the appended papers from a late number of the Paris Journal of Pharmacy.
The Edinburgh Pharmacopœia has an extract of scammony among its officinal preparations, prepared by treating scammony with proof spirit, and evaporating the solution. It is described as of a dirty greenish brown color. This color, however, is not a necessary accompaniment, but is owing either to some coloring matter being dissolved in the menstruum or to the partial oxydation of the dissolved substance under the influence of the air and the heat of the operation.
The ethereal solution of scammony resin, when gradually evaporated, and without exposure to heat, leaves a colorless or amber-colored resin, perfectly transparent and soluble in alcohol; when heated, however, {10} during the operation, more or less insoluble matter of a dark color is found. Sometimes the ethereal solution, when spontaneously evaporated, leaves a dark residuum, but a second solution and evaporation leave it as above described.