The influence of cocaine, atropine, and caffeine on the heart and bloodvessels / by H.G. Beyer.

  • Beyer, Henry Gustav, 1850-1918.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: The influence of cocaine, atropine, and caffeine on the heart and bloodvessels / by H.G. Beyer. 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.

    31/36 (page 29)
    normally produce this effect from the start, instead of running caffeinized saline through the vessels, normal saline was turned on, and occasional injections of 20 mimims of the solution made directly into the circulation, and the result was invariably an increase in the outflow denoting a slight dilatation of the arterioles. When towards the end of the experiment again caffeinized saline was turned on for eight minutes, the outflow per minute became about three times that of the normal, showing that the effect is constant, and that the first decrease in the outflow must have been due to other causes. The conclusion, therefore, is that caffeine in small as well as large doses produces dilatation of the bloodvessels in the terrapin ; any rise in arterial pressure due to caffeine is, consequently, to be explained only by the stimulating effect caffeine exerts on the heart itself. EXPLANATION OF PLATES. All the tracings were taken by means of a mercury manometer connected with the cardiac end of the outflow tube, and to be read from left to right. PLATE I. From Experiment XXIV.—a, normal tracings ; 6 and c, beginning to show the effect of cocaine, and finally passing into d, the state in which two auricular to one ventricular contractions occur; of the two auricular contractions, one is pre-systolic, the other post-systolic. The tracings shown in & and c do not always occur, and more often, especially after the first observation has been made, the transition from the normal to the abnormal sequence is sudden. PLATE II Tracings a and & are from Experiment XXV., with atropine.—a showing the primary effect of stimulation of the ventricle when it becomes reduced in size, but is still beating at an increased rate and following the auricular contractions regularly ; 6 shows the condition in which two auricular and one ventricular beats occur. Tracings c and d are from Experiment XV., showing the effect of cocaine and atropine combined on the heart. Note the diastolic descent in the curves, not seen when either of the drugs is used alone. The same will be noticed in e and /, which are taken from Experiment XXVIII., with cocaine and muscarine combined, showing that either cocaine and atropine, or cocaine and muscarine, act on the heart in the same general direction.