July i, 1884.] 



THE TROPICAL AGRICULTURIST, 



45 



than one per cent up to more than ten per cent — as 

 well as the absence of any definite or recognizable rela- 

 tion between the external characters of a sample and the 

 amount of alkaloids contained in it, I concluded that it 

 would be best to operate upon bark of previously ascert- 

 ained alkoloidal contents, and to choose such as coutained 

 a medium percentage, as shown by the following figures:— 



Grains 

 Per cent. 



Quinine 21 



Ginchonidine 1 <! 



Oinchonine 2-03 or 



Amorphous alkaloid .... I'" 11 



per lb. 

 147 

 112 



1 l_'l 

 7') 



Total alkaloids 673 471} 



Liquid extract made from this bark by a process capable 

 of effecting the entire removal of the alkaloids, and stand, 

 ardized so that 1 fluid ounce would correspond to 1 ounce 

 of the hark, ought, therefore, in accordance with the above 

 figures, to contain about 29§ grains of total alkaloid per 

 fluid ounce, with the several alkaloids in the following 

 proportions: — 



Grains. 



Quinine 9'2 



Oinchonidine T"0 



Cinchonine °9 



Amorphous alkaloids 4'4 



Total alkaloids 295 

 This would be rather more than 5 per cent — the pro- 

 p irtion recommended by Professor Redwood ; but for the 

 purpose in view the bark was considered to be sufficiently 

 near to the proper standard. 



In operating upon one pound of this bark in the manner 

 directed, I found that when 10 pints of liquid had passed 

 through, the percolate still gave a precipitate when mixed 

 with caustic soda in excess; the operation was therefore 

 continued until the percolate had ceased to give this re- 

 action. On reaching that point 13| pints of liquid had 

 passed through. The percolate was sensibly acid, even 

 while thus dilute, and when evaporated down to one pint 

 was much more strongly acid. On cooling and diluting 

 the liquor with water it deposited some brown floeculent 

 material, which, when separated by filtration, washed and 

 dried, was found to weigh 27} grains and to contain PI 

 grain quinine with traces of the other alkaloids. The filter- 

 ed liquid evaporated to dryness left a residue of solid ex- 

 tract weighing 4} ounces, which was found on analysis to 

 contain 1296 per cent total alkaloid.* 



According to the directions given by Professor Redwoood 

 in his paper for preparing the liquid extract from this 

 solid extratct, it is easy either to obtain a preparation 

 that shall contain 5 per cent total alkaloid, or one con- 

 taining in a given bulk exactly as much total alkaloid as 

 the corresponding weight of bark operated upon. But to 

 fulfil both these conditions it would be necessary to use 

 bark containing exactly 625 per cent total alkaloids. In 

 the present case, for instance, 1 ounce of the bark con- 

 tained nearly 294 grains of total alkaloids, and by dis- 

 solving to the volume of a fluid ounce as much extract 

 as contained that quantity of total alkaloids (227i grains,, 

 of course the fluid ounce of liquid extract would to 

 that degree correspond to 1 ounce of the bark it was 



made from, and would contain 6'73 per cent of total 

 alkaloid. To bring it nearer to Professor Redwood's stand- 

 aid of 5 per cent, 1G8J grains of the dry solid extract 

 was dissolved to the volume of one fluid ounce, and on 

 analysis the product gave : — 



Grains. 



Quinine 589 



Cinehonidine 590 



Oinchonine 569 



Amorphous alkalo id 4'39 



Total 21-87=5 per cent. 



By comparing these results with those furnished by the 

 analysis of the bark operated upon, it will at once be 

 seen that the relative proportions of the alkaloids are 

 different as compared with the orginal bark, and that 

 there is in the extract a relative deficiency of quinine, 

 together with a relative preponderance of amorphous 

 alkaloid. There was, therefore, some reason to infer that 

 the extract did not adequately represent the bark from 

 which it was made, inasmuch as it contained a smaller 

 proportion of the most valuable and important alkaloid 

 quinine, and a much larger relative proportion of the less 

 valuable amorphous alkaloid, which is by some considered 

 to be objectionable from a medicinal point of view. In 

 addition it will be seen that the quantity of solid extract 

 requisite to make one fluid ounce of liquid extract re- 

 presenting one ounce of the bark, was very much larger than 

 the quantity obtained from one ounce of bark, or 227^ 

 grains instead of 115^ grains. 



This leads to a consideration of the further desideratum, 

 that in preparing liquid extract " the bark should be ex- 

 hausted of its alkaloids by the process adopted, ' and it 

 must be pointed out that as yet no evidence has been 

 furnished that the suggested process is capable of effect- 

 ing such a result. The device just referred to, of taking 

 as much solid extract as contains a desired quantity of 

 total alkaloids iu order to make a certain bulk of liquid 

 extract, is one very safe to rely upon for standardizing 

 the amount of total alkaloid in the latter preparation ; 

 but since it has no kind of collection with the entire 

 removal of the alkaloids from the bark used, the efficacy 

 of the process in this respect must be tested in another 

 way. In order to obtain some evidence on this point the 

 total quantities of the several Alkaloids in the solid extract 

 above referred to were computed on the basis of the 

 analysis and compared with the quantities contained in 

 tin- hark from which it was made, as follows : — 

 One pound 4} oz. of 



* I was unable to obtaiu satisfactory results in the ana- 

 lysis of this extract according to the method directed by 

 Professor Redwood. On treating 20 grains of the extract 

 with caustic soda, a slimy precipitate was thrown down, 

 and the liquid became so thick that it could not be filtered 

 readily. After washing and drying this precipitate, it 

 weighed only 0'92 grain, though it was only in part alkal- 

 oid, while the quantity of alkaloid was found by another 

 method to be 2*59 grains. Part of this deficiency was in 

 all probability owing to the viscous state of the extract 

 solution when mixed with caustic soda, but in part it was 

 a consequent of the solvent action of the water present. 

 This was ascestained by operating upon a quantity of dry 

 quinine sulphate containing 2*59 grains of alkaloid dis- 

 solved in one fluid ounce of water, and mixed with three 

 fluid drams soda liquor aud washing the precipitate so ol 

 tained. The dried precipitate obtained weighed only I '97 

 grain showing a loss of 0'62 grain. 



Deficiency. 



82-43 



47-30 

 79'95 

 21-97 



of bark solid extract 



contained contained 



Grains. Grains. 



Quinine .... 147 64'57 



Oinchonidine . . 112 G470 



Oinchonine . . . 142} 62-30 



Amorphous alkaloid 70 4803 



471} 23960 231-65 



It is evident from these figures that there was not only a 

 I large deficiency in the amount of total alkaloid, but that 

 the quantities of the individual alkaloids showed dissim- 

 ilar deficiencies, and that, in short, while only one-half of 

 the total alkaloids had been extracted from the bark it 

 was chiefly in regard to the more important alkaloids that 

 this loss was most considerable. Evidently, therefore, the 

 proposed treatment with hydrochloric acid does not furn- 

 ish a preparation that can be considered to represent 

 cinchona bark in such a manner that a fluid ounce shall 

 contain all the valuable medicinal properties of an ounce 

 of that drug. 



In making liquid extract by this process the bark con- 

 sumed is only half represented as regards total alkaloids, 

 for, as already shown, it would be necessary to take the 

 solid extract from nearly two ounces of bark to make one 

 fluid ounce of liquid extract containing as much total al- 

 kaloid as one ounce of the bark, while beyond this the 

 total alka'oid in the liquid extract so produced would be 

 much inferior, as regards the relative proportions of its 

 constituents, to that actually contained in the bark itself. 

 To obtain farther confirmation of this result the residual 

 bark was submitted to analysis, and it was fouud to con- 

 tain 449 per cent total alkaloid.v^The following table 



