March i, 1887.] THE TROPICAL AGRICULTURIST. 



59^ 



have had heavy and early acquaintance with the for- 

 mer, which makes me thaukful if I can get the 

 latter. W. A. Lyktle, 



—3Iadras Mail. 



CHEMICAL EXAMINATION OF COCA 

 LEAVES. 

 I have much pleasure in reporting to you the 

 results of my first attempt at the chemical examin- 

 ation of the leaves of Coca Erythroxylon, which 

 you were good enough to obtain for me. One 

 portion of the sun-dried leaves yielded -514 per 

 cent of crude cocaine alkaloid ; another smaller 

 portion of the sample, which I treated with fully 

 one and-a-half times the proportion of solvent 

 used in the first case, yielded -648 per cent of 

 crude alkaloid. These results are good, but the 

 total amount of alkaloid obtained from the quan- 

 tities of leaves operated on seemed to me too 

 small, viz., 4*2 and 2-6 grains respectively, to admit 

 of an accurate determination of the pure alkaloid 

 being made by the process followed. In assaying 

 the leaves by this process, indeed, it is not custom- 

 ary to proceed further than the actual determin- 

 ation of the crude alkaloid. Determinations on 

 the large scale shew the proportion of impurities 

 (another alkaloid called hygrine and decompos- 

 ition products,) which usually accompany the crude 

 cocaine, and a corresponding deduction being made 

 from the impure alkaloid obtained by assay, the 

 difference is regarded as a close approximation to 

 the amount of pure alkaloid. I should like to 

 obtain a larger supply of leaves, both for the 

 purpose of trying other methods of extracting 

 the alkaloid, and also to determine for myself 

 the amount of purified alkaloid obtainable from 

 the crude alkaloid. I have before me two 

 leading chemical journals, in both of which the 

 process I used is given, yet the one authority 

 states (giving instances from actual working) that 

 the crude alkaloid usually contains from 20 to 25 

 per cent of impurities, while the other authority 

 gives no examples, but states that the crude al- 

 kaloid " contains on an average 20 per cent of 

 alkaloid with much impurity." The crude alkaloid 

 which I obtained was a clear, almost colourless 

 substance, resembling varnish, which by and bye 

 crystallized, the crystals spreading out from star- 

 shaped nuclei. The crystals even after long drying 

 remained somewhat viscous to the touch. A small 

 portion when laid upon the tongue and pressed 

 against the roof of the mouth had a slightly 

 bitter taste, and about a minute, there was ex- 

 perienced an increasing feeling of numbness. The 

 effect, which was not very strong, but quite marked, 

 passed completely away in a few minutes. A 

 portion of the alkaloid obtained was dissolved in 

 hydrochloric acid to a clear and neutral solution, 

 and evaporated to the consistency of varnish. After 

 standing for some time and being stirred it changed 

 its physical condition to what looked like a moist 

 nearly white amorphous powder, but, under the 

 microscope, its structure was revealed as a mass of 

 clear, but very r^inute, prismatic crystals. This is 

 the cocaine hydrochlorate, the use of which as a local 

 an:esthetic is now fairly established. A little of it 

 placed upon the tongue soon produced a sensation 

 (or want of sensation ) resembling that of a painless 

 blister. I dissolved the salt in water, adding a 

 minute quantity of salicylic acid, to prevent the 

 growth of low organisms in the solution. I have 

 ent you a portion of this solution, which is clear 

 and but slightly tinged with colour. A good way 

 to test the effect of it on the mucous membrane 

 of the mouth, is to put a drop of it on a small 

 piece ot blottmg paper, which is then pressed 



between the tongue and the roof of the mouth. 

 A comparatively short time ago, the crystallized 

 hydrochlorate of cocaine was retailed in Colombo 

 at E2-.50 per grain, now it may be had for 25 cts. 

 per grain. 



As I have not in the course of my reading seen 

 any analysis of the ash of coca leaves, I used a 

 portion of the sample of leaves to make an analysis 

 of the mineral ingredients left after burning the 

 Leaves. This is interesting, as showing the in- 

 organic matter removed from the soil by a crop 

 of coca leaves. 



The sun-dried leaves gave off 10*8 per cent of 

 moisture, when dried at 212° Fahr., and when burned, 

 yielded fully 6 per cent of ash, including carbonic 

 acid, which is not an ingredient of the leaf, but 

 a product of combustion. The following are the 

 detailed results : — 



Oomposition of the ash of coca leaves. 

 Silica ... ... ... ... 306 



Oxide of iron &c., ... ... 338 



Lime ... ... ... ... 27-86 



Magnesia ... ... ... 8*50 



Sodium chloride ... ... ... 574 



Postassium chloride ... ... 1'26 



Potash... ... ... ..: 13-94 



Phosphoric acid ... ... ... 16.81 



Sulphuric acid ... ... ... 4'61 



Carbonic acid ... ... ... 14'84 



lOO'OO 

 Since writing the above, I have come upon and 

 interesting research into the composition of tea 

 leaves, in the January number of the Journal 

 of the Chemical Society, which, by analogy, 

 may throw some light on the discrepancy of the 

 two authorities referred to on the matter of the 

 amount of pure cocaine obtainable from the 

 crude alkaloid. 0. Kellner has made systematic 

 analyses of fresh tea leaves plucked from May to 

 November, and it would appear from his tables 

 of analyses that the amount of ethereal extract 

 and of the alkaloid theine are variable, and in 

 something like inverse proportion to each 

 other. In May the amount of ethereal extract 

 was 6"48 per cent, and the theine 2-85 per ct. calcu- 

 lated on the dry leaf, while, in November the 

 figures were 22"19 and 1.00 respectively The 

 constituents of the ash shew similar changes. 

 The potash e, g. in May constitutes 49 06 per cent, 

 of the ash, and it gradually decreases, till, at the 

 end of November, it is only 17'31 per cent. 

 Conversely the lime in May is 11-95 per cent, an 

 at the end of November 30.46 per cent. 



M. COCHRAN. 

 Colombo, 7th Feb. 1887. 



Substitute fok Coffee amongst the Natives. — 

 A ]Dlanter has sent us pods of a leguminous plant, 

 asking, — " Have you heard of the new coffee that is 

 now sold at the kaddiea on the road side called 

 To@r attaV Having submitted the question to 

 Mr. W. Ferguson, he writes : — These fruits (pods) 

 are those of the Sesbania J^gyptiaca Persona. The 

 plant is common about cosly lines all over Ceylon 

 and has been grown in the island for several 

 centuries. It is given as a native in Dr. Trimen's list, 

 but though known to the Tamils as Karum-chembai, 

 it has no Sinhalese name and it is not one of 'the 

 Toras, (Cassias, or Cajanus). The leaves are used 

 as poultices, and the wood makes excellent charcoal 

 for gunpowder, but I do not believe the seeds are 

 used for any purpose.* Those of a species of 

 Cassia, had quite a run as a substitute for coffee 

 sometime ago." 



* Our correspondent distinctly states that they are 

 now used as a substitute for coffee. — En. 



