The poisonous constituent of the bark of robinia pseudacacia / by Frederick B. Power.

  • Power, Frederick B. (Frederick Belding), 1853-1927
Date:
[1913?]
Catalogue details

Licence: Public Domain Mark

Credit: The poisonous constituent of the bark of robinia pseudacacia / by Frederick B. Power. Source: Wellcome Collection.

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    sessed the same toxic properties as that previously obtained. It is well known that substances of this character lose their activity to a greater or less extent on keeping, even in a dry state, and that they also undergo change in this respect when their purification is attempted by methods of repeated solution and precipitation or by subjecting them to dialysis. Some change of this nature may have taken place in the material employed bv Professor Kobert for his recent experiments, and this would appear to be the most probable explanation of the results now obtained by him, which, moreover, are so completely at variance with his own earlier observations.* As a specimen of the Robinia protein which had been prepared by myself in 1904 was still available, it was deemed of interest to ascertain whether it still retained its original toxic properties. It was therefore kindly tested with respect to its activity by Dr. H. H. Dale, Director of the. Wellcome Physiological Research Labora¬ tories. An amount of 0.25 gramme was administered by the mouth to a dog, when, after an interval of about an hour, it produced two attacks of vomiting. This result, together with the observations previously recorded, as noted above, clearly demonstrate that the poisonous constituent of Robinia bark is a protein. They cer¬ tainly lend no support to the statement of Professor Kobert that the respective protein, or robin, is a non-poisonous “ phasin,” or to his presumption that the activity of the bark is due either to an alkaloid or a glucoside. There remains to be considered the statement of Professor Kobert (loc. cit., p. 83) that the robin, or protein material pre¬ pared by him was not capable of. hydrolyzing sinigrin, and pos¬ sessed in fact no hydrolyzing action on glucosides, nor did it coagu¬ late milk. His failure to obtain positive results in these experiments was certainly due to no inaccuracy in my observations, as would thereby be implied. Since the receipt of his publication I have again tested in this direction the above-mentioned specimen of * Since writing this paper I have been favored with a private communica¬ tion from Professor Kobert, in which he informs me that his method of testing the hydrolytic action of robin was by mixing a 1 per cent, solution of the protein with a 1 per cent, solution of sinigrin, and observing the result after keeping the mixture for some time, either at the room temperature or at a temperature of 38° C. It is not surprising that under these conditions no odor of mustard oil was perceptible. Apart from the extreme dilution of the robin solution employed, it is probable that in the preparation of the latter the active portion of the protein had been removed.