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.

125/592 (page 119)

$tricle maintaining its systolic spasm, while the rest dilates. Thus, the extreme apex may remain hard and white during the diastole, and even hernial pro- trusions of the ventricle may occur. Finally, the heart is arrested in systole; and as the muscle so hardens, of course all its power of responding to elec- trical or other excitants is lost. In some rare instances, instead of the above series of phenomena, the dias- tolic periods throughout are prolonged and quiet, and after several periods of relaxation, lasting for ten or twenty seconds, final diastolic arrest may occur. As both Boehm {op. cit., p. 163) and Dybkowsky and Pelikan {loc. cit.) have found that the slowing of the heart's beat, the increased energy of con- traction, the irregularity and final systolic arrest, are produced by digitalis after division of the vagi and destruction of the spinal cord, and as both Ackermann (quoted by Boehm, op. cit., p. 158) and Boehm have found that the paralyzing of the peripheral ends of the vagi by atropia does not pre- vent the phenomena just alluded to, it is evident that the drug acts directly upon the heart-muscle itself, a conclusion which is confirmed by Eulenburg and Ehrenhaus (quoted by Dr. T. Lauder Brunton, On Digitalis^ London, 1868, p. 51), who found that digitalis, when locally applied, acts at once upon the heart. On the other hand, the inhibitory activity of the peripheral ends of the pneumogastrics is without doubt increased by the drug. There is no stage in which stimulation of the vagi does not cause diastolic arrest. Indeed, Dybkowsky and Pelikan have seen galvanization of the nerves produce such relaxation in the auricles after the ventricles had already become perma- nently contracted. Further, Boehm has found that a stimulation of the pneu- mogastrics which is insufficient to make itself felt before poisoning will, after the exhibition of digitalis, cause diastolic arrest lasting for many minutes. It appears, therefore, that the peripheral cardiac inhibitory apparatus shares in the stimulant action of digitalis; and, as Boehm has found that diastolic arrest never takes place in frogs poisoned with the drug, after section of the vagi, it is probable that this rare mode of death is really due to super-exci- tation of the inhibitory cardiac nerves. Rudolf Boehm {op. cit., p. 170) has investigated the influence of digitalis upon the working power of the heart when freed from all connection with the central nervous system. By using the method of Ludwig and Coats, he obtained as a constant result that the amount of work done was increased by small doses of digitalis; that after large doses a similar increase was fol- lowed in a short time by very great diminution in the expenditure of power by the heart, a diminution aj^parently due to imperfect diastole and conse- quent non-admission of serum into the viscus. The elaborate experiments of L. Traube {Gesammelte Beitrage zur Patlio- logie nnd Phjsiologie, Bd. i., Berlin, 1871) upon warm-blooded animals showed that in dogs moderate doses of digitalis produce increased arterial _ pressure, with lowering of the rate of the cardiac pulsation. When toxic doses were used, these phenomena were followed by increase of the pulse-$