This chemist digested Coca leaves, cut into very small pieces, in alcohol (at 55°), for several days, adding sulphuric acid. The tincture which resulted from this operation was separated by expression, filtered, and treated with slaked lime. The liquid, which was primarily of a greenish-brown, was both divested of a part of its chlorophyll and also of a certain waxy substance. Niemann then neutralized this with sulphuric acid and evaporated it over a water-bath. The residue was then treated with water, which caused the separation of the rest of the chlorophyll and of the sulphate of Cocaine that it contained, and which was precipitated by means of the carbonate of sodium. He separated it finally with ether and purified it by several re-crystallizations in alcohol. This process was modified by Lassen, who precipitated the aqueous solution with the subacetate of lead.
In this way he was able to obtain about six grammes of Cocaine from a kilogramme of Coca leaves.
Moreno y Maïz proposed a third process. He mixed intimately, slaked lime with finely-pulverized Coca leaves, letting the mixture stand for nearly twenty-four hours, in order that the lime might react suitably on the alkaloid, imitating in that, the Indian who mixes with his quid the llipta, of which we have already spoken. He afterward lixiviates it with alcohol at 40°.
II.—PHYSICAL STUDY.
We have reviewed the works of the different authors who occupied themselves with Coca; their various labors, although very interesting, did not reach the famous discovery of local anæsthesia, and it is to Köller, of Vienna[10], that the honor belongs of having brought to light the remarkable effect of Cocaine when applied to the conjunctival membrane.
This soon awakened general curiosity. From all quarters came works on the subject. Reuss, Kœnigstein, Jellinck, Schrotter, Knapp and others hastened to give to the profession the result of their researches.
In France enthusiasm was not less strong, nor less prompt, all those whom this discovery interested undertook a series of experiments with Cocaine[11].
Among the first experimenters we must mention specially, Prof. Panas, Prof. Vulpian, Prof. Dujardin-Beaumetz, Dr. Terrier, Dr. Trousseau, Dr. Dehenne.
Prof. Panas reports in a communication made by him to the Académie de Médecine[12] what he has observed.
He states, besides, that in nearly all respects his personal investigations are confirmatory of those made by Köller.