4 6 



THE TROPICAL AGRICULTURIST. 



[July i, 1884. 



gives a general resume of these results, from which it 

 will be seen that the residual bark contained nearly as 

 much alkaloid as had been extracted by the process, and 

 that as regards the relative proportion of quinine it con- 

 tained it was even better than before treatment: — 



In the following number of the Pharmaceutical Journal 

 Mr. Redwood writes: — 



LIQUID EXTRACT OF CINCHONA. 



Sir, — In the experiments I made for the purpose of ob- 

 taining data on which to found the process I have suggested 

 for liquid extract of cinchona, a sample of succirubra bark 

 was first operated upon which, tested by De Vrij's method 

 with limi' and alcohol, yielded 48 per cent, of total alkal- 

 oids; and this in No. b'O powder, when treated as I have 

 described with hydrochloric acid and water, and reduced 

 to a dry extract, gave by precipitation with soda an amount 

 of alkaloid corresponding to 4*3 per cent of the bark 

 used. In this operation not only was the percolated liquid 

 acid, but the marc at the end of the process was slightly so 

 also, and viewing this in connection with the fineness of 

 division of the bark and the known action of hydrochloric 

 acid as a solvent of cinchona alkaloids, the result did not ex- 

 ceed what appeared to me reasonable to expect. I took the 

 near approximation of the amount of alkaloids in the extract 

 to that in the bark yielding the extract as indicating a pract- 

 ical exhaustion of the bark, although, no doubt, further 

 evidence would be looked for to establish complete exhaus- 

 tion, especially as the method I adopted for estimating the 

 alkaloids in the extract is not a rigidly exact one. My ob- 

 ject was to devise a method as little complicated as possi- 

 ble and suitable for adoption by pharmacists geuerally, but 

 the desire to submit such for criticism at a pharmaeeutii al 

 meeting before the meetings had terminated fo the season 

 vendered it necessary to leave several parts of the investig- 

 ation to be subsequently completed. 



Since the publication of my paper I have repeated the 

 process upon further samples of East Indian succirubra bark 

 with results similar to those I have already recorded. The 

 barks I have used have contained from 4'8 to 5*5 per cent 

 of total alkaloids, and with these I have found that when 

 the percolated liquid has reached a quantity corresponding 

 to ten or, at most, eleven pints of percolate from a pound 

 of the bark, it has ceased to give a precipitate with soda. 

 The marc, on being then treated with fresh hydrochloric 

 acid, although yielding a solution which gives a dark brown 

 extract with soda, some of which may be percipitated, has 

 afforded me no distinct evidence of the presence of alkaloid. 

 By a more searching process, however, with lime and alcohol 

 (he Vrij's method) a small quantity of mixed alkaloids 

 may be extracted, amounting, I have found, to about a 

 tinth part of the alkaloids originally present in the bark, 

 as determined by the same method. Thus a bark contain- 

 ing 5 per cent of alkaloids, after being exhausted by the 

 hydrochloric acid process, yielded 053 per cent of additional 

 alkaloids, the same method of estimation being adopted in 

 both cases. 



The results obtained by Mr. Oownley, and published in 

 last week's Journal, appear to me to he explfcKble only by 

 assuming that the sample of bark he has operated upon 



differed very much from any of those I have employed. 

 It was richer in alkaloids thau any of mine, but I do not 

 think that alone would account for the results obtained by 

 him. I have not yet worked on barks so rich in alkaloids 

 as the one he describes, but am prepared to find that some 

 modification of the process, especially in regard to the pro- 

 portion of hydrochloric acid, may be necessary to meet the 

 requirement of very rich barks. I attach importance to 

 the degree of comminution of the bark in treating it by 

 this process, and the fact that Mr. Oownley found it 

 necessary to continue the percolation much further than I 

 have done has raised a doubt as to whether he used the 

 bark in sufficiently fine powder.— T. Redwood. 



TIIE RESIN INDUSTRY IN THE LANDS 

 DEPARTMENT.* 



BY A. ItENARD. 



The Landes department is the most important centre in 

 France for the production of resin. This large triangular 

 space of about fourteen thousand square metres, bounded 

 upon one side by the ocean, and on the others by the Adour, 

 the cultivated heights of the Lot et Garonne department, 

 and the vineyards of Bordeaux, is an ancient bed of the sea, 

 covered by sand of the Pliocene age. The sandy masses, 

 which in many places are more than eighty metres thick, 

 contain a few beds of clay ; but at only a slight depth there 

 occurs a compact layer, termed " alois." which is traversed 

 with difficulty by the roots of trees, and which is one of the 

 greatest obstacles to forest vegetation. In former. times the 

 rain-water, retained by this compact layer of sandstone, re- 

 mained upon the soil, and transformed the surface of the 

 Landes iuto a vast marsh; but since then numerous drainage 

 have been cut and convey the surplus water to the 

 pods on the shore. In this way the surface has now be- 

 come almost dry, the marshes have disappeared, and the 

 inhabitants of these districts are no longer compelled to raise 

 themselves on stilts to traverse the vast stretches of land, 

 which formerly were impassable to ordinary pedestrains. 



There is no doubt that before the middle ages the greater 

 part of the Landes was covered with forest, at least upon 

 the borders of the sea ; but through the improvidence of 

 the inhabitants these woods had been destroyed, and the 

 sand had commenced its invading march from the sea coast, 

 threatening to swallow all that it met upon its way. The 

 first attempts which were made to reclaim the " dunes " 

 date from the commencement of the eighteenth century; but 

 it was Bremontier who, between 1787 and 1703, definitively 

 solved the problem of the plantation of the Landes, he suc- 

 ig in consolidating more than 250 hectares of shifting 

 " dunes." In the present day an immense forest of pines 

 covers all this vast extent of territory, formerly uncultivated 

 and marshy, and forms an impassable barrier to advance of 

 the " dunes" from seaward. 



The maritime pine is the tree chosen, to the exclusion of 

 almost all others, by the Landais cultivators, and its repro- 

 duction is effected either from seeds or from cuttings; but 

 the finest trees are those obtained from seeds, and this is the 

 method generally followed. The sowing takes place natur- 

 ally. Every four or five years a clearing is made by cutting 

 down the least vigorous of the young trees so as to allow 

 the others to develop under the most favourable conditions, 

 and at the end of twenty-five or thirty years the trees areabout 

 one and a half or two metres apart. Those which at this 

 stage still requirp to be removed are bled to death. This 

 operation consists in making two large gashes on opposite 

 sides of the tree, the turpentine that exudes being collected 

 by one of the methods described subsequently. I r n«ler these 

 conditions the tree is quickly exhausted, and at the end of 

 four or five years is cut down. Eventually a final selection 

 is made of the finest trees in the pignada, which are to be 

 preserved for regular working, care being taken that they 

 shall he equidistant at about eight metres; all the others 

 are then bled to death and cut down at the end of from 

 five to seven yeats. When the trees selected for preservation, 

 which are called "pins de place" have attained a diameter 

 of 30 to 35 centimetres they are ready for working. 



By means of a sharp blade, slightly curved and fixed per- 

 pendicularly at the end of a wooden handle, an incision is 



* From the Monitenr Scieutifique, vol. xiii., p. 945. 



