The physiological standardization of digitalis / by Charles Wallis Edmunds and Worth Hale.

  • Charles Wallis Edmunds
Date:
1909
Catalogue details

Licence: In copyright

Credit: The physiological standardization of digitalis / by Charles Wallis Edmunds and Worth Hale. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    one-hour” method. with any degree of accuracy. With the “one-hour” As between them it is impossible to choose method we have the advantage of there being no delay, it being possible to assay a preparation in three or four hours, and it probably takes fewer frogs than the “twelve-hour” method. On the other hand, with the latter method, although taking four or five days to complete the assay, it need not interfere with other work, as the frogs can be injected late in the afternoon and examined the next morning. Between these two methods, then, as far as can be judged, it is largely a question of personal preference and convenience, at least in the light of our pres- ent knowledge. Our results do not show that they give the same rela- tive values to the four specimens examined by them, and as to which is correct it is impossible to say. They do roughly agree in that Bur- roughs,. Wellcome & Co.’s Concentrated Tincture and Digitol are both stronger than the two fluid extracts of Parke, Davis & Co. and Sharpe & Dohme. This relationship is confirmed by every other method which we employed, excepting that using the toxic dose as found on cats. It would not seem, therefore, to be unreasonable to suppose that such a relationship would probably exist in man. As to the desirability of manufacturing houses standardizing their preparations belonging to the digitalis series there can be no question. It is true that the official preparations examined herewith are ap- proximately of the same strength, but the'crude drug obtained in another year may represent altogether a different toxicity to that employed in the manufacture of these preparations, and the only way at present to avoid like variations in the tinctures and fluid extracts is to standardize them by physiological methods. It is not claimed that such methods are infallible. They certainly are not, as we have shown; but, as we have also shown, most of the apparent discrepancies are due to the fact that actions upon quite different physiological functions are taken as a measure of activity. Such discrepancies can be avoided by the adoption of one or the other of these frog methods, and if it is thought necessary the results obtained can be confirmed by blood-pressure experiments upon cats or, preferably, dogs. We believe the chief point to be kept in mind is that, in spite of annoying individual discrepancies, there is a general agreement be- tween the various methods. This agreement, too, is much more com- plete in the case of those methods in which the toxic effect is due to an action upon the heart. A preparation found weak by one method appears weak by all methods, and one showing marked activity by one shows the same result in all. The second part of the research, that which is concerned with the different preparations, requires little to be added to that already given in the tables. We have arranged, however, the different preparations in the order of their relative strengths as determined