A treatise on therapeutics : comprising materia medica and toxicology, with especial reference to the application of the physiological action of drugs to clinical medicine / by H.C. Wood, jr.

Horatio Curtis Wood Jr.

Date:: 1874

Credit: A treatise on therapeutics : comprising materia medica and toxicology, with especial reference to the application of the physiological action of drugs to clinical medicine / by H.C. Wood, jr. Source: Wellcome Collection.

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$the death of the batrachian ; but that this diminution for from twenty-five minutes to an hour was immediately suspended by section of the cord high up, the reflex activity returning at once to its normal state; that after large doses the reflex movements were almost abolished in five minutes, and continued until death, but at any time during the first ten or twenty minutes could at once be restored by section of the upper cord; that, both after large and small toxic doses, a time finally came when division of the cord had no power to restore the lost reflex functions. The second series of experiments were directed to discovering whether the action upon the inhibitory reflex centres and the cord was a direct one, or was simply the result of the altered circulation. In this part of the investigation, the hearts of frogs were cut out, or their motion arrested by the local application of a concentrated solution of the nitrate of potash, or rendered slower by a dilute solution of the same salt, and the eff'ects of these various procedures upon the reflex activity were studied. It was found that slowing of the heart's action did excite the Setschenow's centre, but not to nearly so great an extent as did digitalis, and that minute doses of digitalis sometimes stimulated the Setschenow's ganglion and lowered reflex activity before the heart was sensibly aff'ected. In regard to the spinal cord it was proven that when the heart was killed by the local action of potash the reflex functions of the spinal ganglia remained intact for a much longer period than when digitalis was administered. The action of digitalis upon the heart of the frog was, I believe, first inves- tigated by M. Yulpian {Comptes-Eendus de la SociiU de Biologic^ 1855, p. 70), who has been followed by numerous observers, among whom may be mentioned W. Dybkowsky and E. Pelikan {Zeitschrift fur WissenschaftUche Zoologie, Bd. xi., 1862), A. B. Meyer (Arbeiten avs dem Physiologischen Imtitid zu Zurich, quoted by Boehm), Legros and Legroux (quoted by Gourvat), Claude Bernard (quoted by Gourvat), Rudolf Boehm {Pfliiger's Archivfiir Phjsiologie,m. v., 1872), Homolle {Archives Generalesde Mede- cine, July, 1861), Gourvat {Gazette Medicale de Paris, 1871), FothergiU {Digitalis, London, 1871), Fagge and Stevenson {Proceedings of the Royal Society, London, vol. xiv.). The statements of these investigators agree in all essential points. One or two of them have occasionally noted a primary brief acceleration of the heart's action; but the rarity of its occurrence shows that it has been prob- ably produced by some extraneous unnoted influence. The first distinctive action of the drug is a marked lessening of the num- ber of cardiac beats per minute, due to a prolongation of the diastole, which may be complete, but is more generally divided by an abortive attempt at ven- tricular contraction. The systole is abnormally energetic, so that the ven- tricles become white as the last drop of blood is squeezed out of them. As the action of the drug becomes more intense, the rhythm of the heart is very much affected, the ventricle and auricle no longer beating in accord^ At the same time the diastole generally becomes imperfect, one portion of the ven-$