The only alkaloids likely to remain in the prepared opium, and capable of producing well-marked physiological results, are morphine, codeine and narceine.
Compared with morphine, codeine and the other alkaloids are only slightly narcotizing.
A small amount of morphine and codeine is also manufactured in India for medicinal use.
Thebenine and morphothebaine, from both codeine and thebaine, thereby establishing their connexion.
But codeine can also be made from morphine.
Morphine, in the pure state, can be sublimed, but codeine and narceine are said not to give a sublimate.
In the cough of phthisis minute doses are of service, but in this particular disease morphine is frequently better replaced by codeine or by heroin, which checks irritable coughs without the narcotism following upon the administration of morphine.
Tannic acid, for instance, precipitates codeine as a tannate, salts of many of the heavy metals form precipitates of meconates and sulphates, whilst the various alkalis, alkaline carbonates and ammonia precipitate the important alkaloids.
As a matter of fact, Grimaux, in 1881, showed codeine to be a methylmorphine, and in 1903 Ach and L.
Cotarnine IV.Narceine The chemistry of morphine, codeine and thebaine is exceedingly complicated, and the literature enormous.