Ergot and its active principles / H.H. Dale.

  • Henry Hallett Dale
Date:
[1912?]
Catalogue details

Licence: Public Domain Mark

Credit: Ergot and its active principles / H.H. Dale. Source: Wellcome Collection.

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    ERGOT AND ITS ACTIVE PRINCIPLES. H. H. DALE, M. A., M. D. Director of the Wellcome Physiological Research Laboratories, Herne Hill, London, England. Although ergot has long been established as one of the most valuable drugs at the disposal of the physician, its pharmacology remained, until the last few years, in a state of uncertainty and confusion. Several causes contributed to this unsatisfactory result. In the first place the systematic position of ergot, as a fungus, rendered the chemical isolation of its active constituents a matter of peculiar difficulty. The search was further com¬ plicated by the fact that the most diverse opinions prevailed as to the type of physiological action which should be regarded as characteristic of a principle to which the therapeutic effect of ergot could be attributed. To some extent this difficulty still prevails. Not a little of the confusion, again, was due to the al¬ most reckless manner in which successive observers bestowed names suggestive of chemical individuals on the crudest of extracts, or renamed substances isolated by their predecessors, through failure to compare their own results with those already published. As instances of these tendencies may be cited, on the one hand, the name “Ergotin” still used especially in German literature, which was assigned in turn by Wiggers, Bonjean, Wenzell, Wernich, Yvon and others, in each case to a quite different kind of crude extract; and, on the other hand, the names picrosclerotine, and secalin, given by different observers to the one ergot alkaloid which, at that time, had been obtained in pure condition, and which Tanret, who first isolated it, had named “ergotinine.” This isolation of ergotinine by Tanret, in 1875, may be regarded as the first step of real importance towards the recognition of the specific active principle of the drug. It is remarkable, indeed, how nearly the problem was solved at this comparatively early date in the history of its investigation. Tanret’s ergotinine has been found, as already mentioned, by several subsequent observers, and its formula has now been definitely settled by the analyses made by Barger and Carr, whose correction of that originally given has been confirmed by Tanret himself. In one respect Tanret’s results have not been substantiated by recent work. Finding that ergot yielded, in addition to the easily crystallizing alkaloid, a further quantity of alkaloid giving practically identical chemical reactions, but refractory to crystallization, Tanret regarded this latter as an amorphous form of the same alkaloid. In this assumption he was undoubtedly in error, the amorphous alkaloid being, indeed, closely related to, and easily formed from the crystalline, but not chem-