It was Charles Fauvel who first described the anæsthetizing effect of Coca on the pharyngeal mucous membrane[8]. Thanks to this circumstance, he has been able to derive much benefit from the use of Coca in granular pharyngitis which is generally unaffected by any other kind of treatment. Fauvel further showed that the stimulating effect which Coca exercises on all the muscles of the economy, appears to manifest itself specially on all the muscles of the larynx. Hence his apt qualification of the drug, "a tensor _par excellence_ of the vocal cords." In 1880, Von Arep published the results of his physiological researches with Cocaine. He spoke of its double effect on the nervous extremities and on the central nervous system. We approach, on leaving this epoch, the really scientific era, that is to say, that of physiological experiments. All the experiments having been made with Cocaine, we shall speak of it in the next chapter, which will be devoted exclusively to the study of this alkaloid. Before closing, we will mention that it has been claimed frequently that Coca was aphrodisiac. The fact that the Peruvian Venus was represented as holding in her hand a leaf of Coca, was suggested as a proof in support of this opinion. Dr. Unanué speaks of "certain coqueros, eighty years of age and over, and yet capable of such prowess as young men in the prime of life would be proud of." Let us here add that the so-called unhappy consequences of the abuse of Coca are really much more rare than those produced even by tobacco, alcohol or opium. The constant use of reasonable doses of Coca appears to produce a diametrically opposite effect, and the authors, who have had occasion to see a great number of Coca consumers, report cases of astonishing longevity among the Indian coqueros (Tschudy, Campbell, Mantegazza, Unanué). They add that these instances are far from being exceptional. COCAINE. I.—A CHEMICAL STUDY.[9] Cocaine is a crystallized alkaloid which Niemann, a pupil of Prof. Wœhler, succeeded in extracting, in 1859, from some leaves of _Erythroxylon Coca_ and to which he gave the following formula: C³² H² O Az O² Before it was known to him, Wackenroder, Johnston, Gardeke and Maclagan analyzed this plant without succeeding in the isolation of its active principle. Some important works undertaken on this subject by Lassen, Humann and R. Pérey are also quoted. _Properties._—Cocaine is colorless, odorless, and bitter to the taste. It crystallizes in the shape of oblique rhomboid prisms of from four to six facets. It is very soluble in water, less soluble in alcohol, and absolutely insoluble in ether. It does not vaporize below 98°, but if the temperature is greatly increased it is decomposed. It possesses a strongly alkaline reaction. United with acids it forms salts which are very difficult to crystallize.