[146] Cocain is precipitated in colourless inodorous prismatic crystals. It is with difficulty soluble in water, but melts readily in alcohol, and with still more facility in ether. When dissolved in alcohol, the solution becomes a strong alkaline reagent, and has a peculiar slightly bitter taste. When brought in contact with the nerves of the tongue, it possesses the singular property of deadening sensation after a few seconds have elapsed, in the part to which it has been applied, which for a time becomes almost void of feeling. It fuses at a temperature of 208°.4 Fahr., and in cooling resumes its former prismatic crystalline form. When heated beyond this temperature, it changes to a reddish hue, and volatilizes with a strong ammoniacal odour. Only a small portion seems to get liberated by the destructive process. When heated on a platinum disc, it burns away with a bright flame, leaving no residuum. Cocain completely neutralizes acids, although most of the resulting salts seem to crystallize with difficulty, and to remain for a considerable time in an amorphous state. The resultant chloride seemed the most readily formed as well as delicately shaped of the crystals. Cocain exposed in chlorine is followed by such a development of heat that the former is fused. (Compare "Cocain, an Organic Base in the Coca," letter of Professor F. Wöhler to W. Haidinger, acting Fellow of the Imperial Academy of Sciences, presented at the meeting of the Class of Mathematics and Physical Science, 8th March, 1860. See also "On a New Organic Base in the Coca-leaves," Inaugural dissertation on attaining the degree of Doctor of Philosophy at Göttingen, by Albert Niemann of Goslar. Printed at the Göttingen Press, 1860.)
[147] According to Wöhler, this fluid substance admits of being distilled even along with water; its odour strongly recalls Trimethylamin; it is a strong alkaline reagent, but is not bitter to the taste, and forms a white cloud when acids are poured upon it. Its chloride crystallizes readily, but is very volatile. With chloride of platina it forms a flocculent uncrystallized precipitate, which decomposes on the liquid being heated. With chloride of quicksilver, it assumes a dim milky appearance, which is caused by the formation of a substance resembling drops of oil. Hygrin is not poisonous; a few drops given to a rabbit were followed by no perceptible symptoms.
[148] As, judging by the experiments hitherto made, cocain seems to consist of two atoms in juxta-position, there is reason to conjecture that it is destined to be the source of a large number of products of transformation. It is highly probable, as Wöhler has remarked, that cocain may yet be artificially made by a mixture of hygrin with Benzoic acid, or rather with one of the substances forming part of the Benzoyle group.
[149] See Von Tschudi ut suprà, vol. ii. 309.
[150] I append here the most important points on which information is sought respecting the climatic and other conditions of the various Cinchona species as cultivated in South America, concerning which Dr. Junghuhn needed more correct information, and can but express the hope, that, should curiosity or destiny lead the steps of any one of my more earnest readers to Peru, he may succeed by his own observation in solving these questions, my inability to aid more effectively in which has been to me a source of deep mortification. The learned naturalist of Java furnished me with the following particulars:—
"What it behoves us especially to ascertain, respecting which Hasskarl has observed nothing, and Weddell furnishes no accurate information, is comprised in the following questions:
1. What are the highest and lowest limits of the Cinchona Calisaya, or at all events, what is the altitude of the region in which it most abounds?
2. What is the unvarying warmth of the soil, as observed at a depth of 5 feet below the surface?
3. On what soil does it grow most abundantly and luxuriantly? Does it affect rich black mould, in moist forcing soils, or rather dry, stony, barren soils? Does it grow on steep acclivities, or does it seem to prefer gentle slopes or level ground? Can specimens of the soil be procured? What is the description of the rock formation, trachytic, granitic, or gneiss, or are slate or sandstone the characteristic formations?
4. What are the general meteorological conditions, and what is the annual amount of rain-fall? For how many and during what months does it rain, and during what period of the day are the showers heaviest? Does it rain for months at a time, and for how many, and during what months? Or does it not rain at all, in which case is its place supplied by regular afternoon storms? How many days of rain are there in the rainy season of that particular region of the tropical zone? Are the nights and forenoons, as in Java, usually clear until noon? Is it known whether observations have ever been made by the Spanish Creoles as to the amount and duration of the rain-fall? A correct knowledge of the amount of moisture and rain-fall of the Calisaya district is of special importance to all engaged in the cultivation of that plant. Further, frequent observations must be made with the psychrometer in the morning before sunrise, between nine and ten o'clock, at the hour of maximum of temperature, and in the evening, in the forest and in the open ground, that these may afterwards be compared with mine in Java.