Page:Indian Medicinal Plants (Text Part 2).djvu/432

1182 INDIAN MEDICINAL PLANTS

from .925 to .931 ; saponification value, 190 to 193 ; iodine value, 144 to 166; the fatty acids melt at 17° to 19°. It is used on the Continent as a paint oil and for making soft soap. (Hooper.)

The essential oil purified by distillation in a current of steam and extraction with ether, is a mobile liquid boiling at 248-268° ; after repeated distillation from metallic sodium in order to remove as tearoptene, it yields a sesquiterpene C₁₅H₂₄ , as a mobile, colourless oil of aromatic odour, which boils at 256°, and has a density of 0.897 at 15.3°, and is slightly Iævorotatory. This soon resinifies on exposure to air, and on adding concentrated sulphuric acid to its chloroform solution, the liquid becomes first green, then blue, and red on heating. " Cannabene " prepared from this essence by Personne, was a mixture. (J. Ch. S. LXVIIL, pt. I (1895), p. 623.)

Charas, the natural exudation of the plant contains no chlorophyll. On analysis, it was found to contain 33 per cent, of an oil, having the formula C₁₈H₂₄O₂ . As this compound gives rise to all the symptoms of cannabis poisoning, the main effects produced by the drug are due to the action of this.

The ethereal extract from charas has yielded four distinct chemical compounds :—

1. A terpene, boiling at 160-180°. Yield 1.5 per cent.

2. A sesquiterpene, boiling at 258-259°. Yield 2 per cent.

3. A parffin (C 29 H 60 ), m. p. 63-64°. yield 0.15 per cent.

4. A toxic red oil, C₁₈H₂₄O₂ , boiling at 265° under a pressure of 20 mm. Yield 33 per cent, of the charas taken. This is a mixture of at least two compounds having similar physical characters. One of these, of the formula

C₂H₂₆O₂ , has been isolated, and this has been named cannabinol.

The physiological action of the terpenes closely resembles that of the other members of this class, of which ordinary turpentine may be taken as the type. In doses of 0.5 gram, they have very little effect and produce none of the characteristic symptoms of cannabis action. The red oil, on the contrary, is extremely active, and taken in doses of 0.05 gram induces decided intoxication followed by sleep. The symptoms produced by it are peculiar to Cannabis indica, and as none of the other products appears to possess this action, this substance must be regarded as the active constituent of the plant. (J. Ch. S. 1896, T. 539 and 1899, T. 20.)

On the standardisation of preparations of Indian Hemp. In 1908, Mr. Hooper suggested a chemical method of valuing Indian hemp, and proposed that the iodine value of the resinous constituents containing cannabinol should be taken as a gauge of the activity. In the British Medical Journal for May 20th, 1911, p. 1176, Messrs. Marshall and Wigner have examined this method and shown that this method is of no value and could not be used as a substitute for physiological standardisation. According to them, the " acetyl number " should be used for determining the Standardisation. But in a report on the value of the " Acetyl number " by Messrs. Marshall and Wood published in the same journal for June 1, 1912, p. 1234, they came to the conclusion that the Acetyl number cannot be used as a substitute for physiological standardisation.