Variations in the occurence of salicin and salinigrin in different willow and poplar barks / by H.A.D. Jowett and C.E. Potter.

  • Jowett, H. A. D. (Hooper Albert Dickinson)
Date:
[1902]
Catalogue details

Licence: In copyright

Credit: Variations in the occurence of salicin and salinigrin in different willow and poplar barks / by H.A.D. Jowett and C.E. Potter. Source: Wellcome Collection.

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    that the two latter factors above-mentioned should be taken into consideration. Accordingly, two species were collected at different seasons of the year, and, in the case of one species, the bark from the male and female trees was separately col¬ lected and examined. As the influence of these factors had not been considered when most of the specimens were collected and examined, it has only been possible to determine this in the above-mentioned esses. Method of Examination of the Bark. In order to ascertain whether the bark contained salicin or a similar glucoside, it was examined according to the fol¬ lowing method. A convenient quantity of the bark, not exceeding 1000 Gm., was extracted by boiling with water for from three to four hours. The infusion was strained, the marc pressed, and the whole liquid then evaporated to a low bulk, generally about one litre. To the concentrated extract a quantity of lead acetate, equal in weight to 10 per cent, of the bark taken, was added, the mixture boiled for a few minutes, and set aside. After standing for half-an-hour it was strained through calico, and the precipitate well washed with water. The filtrate was then saturated with hydrogen sulphide to remove excess of lead acetate, the lead sulphide filtered off, and well washed with hot water. The filtrate and wash¬ ings were next evaporated to a low bulk under diminished pressure, and the concentrated liquid then set aside to cry¬ stallise. In those cases where an appreciable amount of salicin was present, it crystallised out very readily, and was then drained on the filter pump, washed with a very little cold water, dried on a porous tile, and weighed. In some cases the product obtained was too impure to be considered satisfactory ; it was, therefore, recrystallised from the least possible quantity of hot alcohol, the purified product weighed, and the mean of the two weights taken as the amount of salicin contained in the bark examined. When no crystals separated even after inoculation with a crystal of salicin, the syrupy extract was taken up with dry sawdust (which had previously