760
ELEMENTS OF MATEUIA MEOICA.
tifflii; purging nuts of some authors), in size and shape are very simil (Uto castor seeds. Viewed laterally, their shape is oval or oval-oblih'S'seen from either extremity, they have a rounded or imperfectly quadra 11ular form. ‘ " ‘ " . . . . , a
2 1
Their length does not exceed six lines ; their thickness lSto 3 lines ; their breadth, 3 or 4 lines. Sometimes the surface o
the seeds is yellowish, owing to the presence of an investing lauu» a(epidermis ?). The testa is dark-brown, or blackish, and is marked lVlt 1the ramifications of the raphe. The endocarp, or internal seed-coat, lSthin, brittle, and of a light colour. It incloses a yellowish oily alb 11 'men, which envelopes the embryo, whose cotyledons are foliaceous &membranous. The seeds arc without odour; their taste is at first Hid 1and oleaginous, afterwards acrid and burning. When heated, d> e )evolve an acrid vapour.
According to Dr. Nimmo (Quart. Journ. of Science, vol. xiii. p-100 parts of the seeds consist of
Shell or seed-coats . 36
Kernel, or nucleus .. 64
100
Composition. —Croton seeds were analyzed by Brandes (Gtu^ 11 '’Handb. d. Chem. Bd. ii. S. 1320), with the following results:—
Volatile oil . traces.
Fixed oil, with crotonic acid, and an alkaloid (crotonin) _ 1700
Crotonates and colouring matter . 0-32
Brownish yellow resin, insoluble in ether. 100
Stearine and wax . 0 65
Extractive, sugar, and malates of potash and lime . 2 05
Starchy matter, with phosphates of lime and magnesia. 5 71
Gum, and gummoin. 10T7
Albumen . 101
Gluten . 2 00
Seed-coats, and woody fibre of the nucleus . 39-00
Water. 22 50
Croton seeds
101-41
1 . Crotonic Acid. —Though this acid exists ready formed in the seed, yet an add> 1 . (S
quantity of it is obtained when the oil is saponified. Brandes thinks that there e - j sin the seeds an extremely acrid volatile oil, which, by the action of air and wa ^jj’jobconverted into crotonic acid. This acid is a volatile, very acrid, fatty acid, 'congeals at 23° F., and, when heated a few degrees above 32° F., is converted , aSvapour, having a strong nauseous odour, and which irritates the eyes and nose. ! r ti°an acrid taste, and acts as a powerful local irritant. It is to this acid that the c at . fl uand poisonous qualities of croton oil are principally referrible. Pelletier and C aVthink that it is not sufficiently energetic to be the sole active principle. It uinte ! 0 |)at ebases forming a class of salts called crotonates, which are inodorous. The cro teof ammonia precipitates the salts of lead, copper, and silver, white; and the sU ‘ jnof iron, yellow. Crotonate of potash is crystalline, and dissolves, with diffi cU . f e rSalcohol. Crotonate of barytes is soluble in water ; but crotonate of magnesiaslightly soluble only in this liquid. ^ a ye
2. Crotonin. —The alkali which Brandes found in these seeds, and to which be ; s
the name of Crotonin, appears to he identical with the Tiglin of Adrien de Jussie 11 - n
crystalline, has an alkaline reaction, is fusible and combustible with flame, h? a 'carbonaceous residuum. It is insoluble in water, dissolves very slightly only I'VjoiiSbut easily in hot, alcohol. If sulphuric or phosphoric acid be added to the s P ir ,,resolution, small prisms (sulphate or phosphate of crotonin P), decomposable .?wi,’iiil» sobtained by slow evaporation. Soubeiran ( Nouv. Truite de Pharm. t. ii. p. W3;
that crotonin is a combination of magnesia with a fatty acid.