1. Battle’s seems to vary in composition. Tardieu found in a packet of 19 grains, 1½ grain of strychnia, or 7·7 per cent., the rest being Potato starch and Prussian blue. Woodman and Tidy (For. Med. p. 329) found 23 per cent. strychnia, with sugar, flour, and Prussian blue. Bernays found 10·7 per cent. of strychnia, with flour and Prussian blue. (Barlow’s case.)
2. Butler’s contains flour, soot, and about 5 per cent. strychnia. Sometimes it contains Prussian blue, and sometimes carbonate of barium in place of strychnia.
3. Gibson’s contains half a grain of strychnia in each powder.
4. Miller’s Rat Powder contains oatmeal, and about 6 per cent. of nux vomica (equal to 0·023 strychnia and 0·067 brucia). (Blyth, Man. of Prac. Chem. p. 317.)
5. Marsden’s Vermin and Insect Killer: one packet contains ¾ grain strychnia. (Lancet, April 19, 1856.)
6. Barber’s “Magic Vermin Killer Powders” weigh 28 grains and contain 10 per cent. of strychnia. “Hunter’s Infallible” also contains it.
In Keating’s Insect Powder I have found no strychnia nor arsenic.
BRUCIA.
C23H26N2O4,4H2O, is probably derived from strychnia by the substitution of two molecules of methoxyl (CH3O) for two atoms of hydrogen (Shenstone, Chem. Soc. Journal, Feb., 1883), hence might be named dimethoxystrychnia. But efforts to change it into strychnia have, as yet, been unsuccessful. All plants containing strychnia contain also brucia. In false Angostura bark the latter much predominates. It occurs in needles or 4-sided monoclinic prisms (rarely in tables), colourless, intensely bitter, lævo-rotatory to a less extent than strychnia, but more soluble in water, alcohol, &c., hence remaining in the mother liquors in the preparation of strychnia. Insoluble in pure ether. It melts at 151° C. (Blyth), and produces a scanty amorphous sublimate near its temperature of decomposition. The salts are neutral, easily soluble in water, and crystallize in needles (the acetate with difficulty). Its physiological action is the same as strychnia, but six or seven times weaker.
With the general reagents for alkaloids brucia gives precipitates. With concent. nitric acid it gives a deep-red colour, changing to orange, and finally to yellow. A trace of stannous chloride (protochloride of tin) turns the red solution purple: excess bleaches it.[98] This test is very delicate. In former times commercial strychnia always contained brucia, hence the coloration by nitric acid was even looked upon as a test for strychnia (see p. 125, and p. 156). But, as the strychnia now sold is generally pure, it gives no colour with nitric acid in the cold. Therefore, if both strychnia and brucia are found in a product extracted from the animal tissues, it follows that Nux Vomica, or one of the plants, or their preparations, has been used, and not the pure alkaloid. The microscope in this case will generally detect some of the vegetal tissue or hairs in the stomach.