Researches into the antagonism of medicines : being the report of the Edinburgh Committee of the British Medical Association / by John Hughes Bennett, chairman and reporter.

  • British Medical Association. Edinburgh Committee.
Date:
1875
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Licence: Public Domain Mark

Credit: Researches into the antagonism of medicines : being the report of the Edinburgh Committee of the British Medical Association / by John Hughes Bennett, chairman and reporter. 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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    siological action of meconate of morphia on rabbits and dogs may be drawn. 1. In both animals, meconate of morphia acts on the encephalon and on the spinal cord, but in the case of dogs the action is more cerebral, while in rabbits it is more spinal. 2. As Dr. John Harley states,* either delirium or hypnotic effects may be produced. In the experiments recorded, hypnotism was the pre- dominant effect. 3. In the case of rabbits, death is often produced by con- vulsions. 4. In both cases, while deeply under the influence of the drug, as stimulation of the motor nerves caused muscular contractions, we must hold that the sensibility and conducting power of the nerves are not destroyed. 5. In both cases, stimulation of the vagus in the neck causes stoppage of the action of the heart. Consequently, the vaso-inhibitoiy fibres in the vagus are not paralysed by meconate of morphia. It is possible, as Harley appears to think, t that these fibres may be irritated. 6. Stimulation of the sympathetic in both cases causes dilatation of the pupil. Consequently the sympathetic trunk is not paralysed, and the contraction of the pupil must be owing to the cranial origins of the third nerve being irritated, thus causing contraction of the circular fibres of the iris, governed by that nerve, and consequent contraction of the pupil.^ 7. Morphia may affect the action of certain nerves by paralysing the nerve centres from which they issue, but the nerves themselves appa- rently still retain sensibility and conductivity. The experiments on the physiological action of meconate of morphia are shortly summarised in the following table. * Harley, Old Vegetable Neurotics. + See Harley, Action on the Pupils, pp. 136-137. t Harley lays great stress on the action of morphia on the vagus, but his facts do not appear to warrant his conclusions. He says (p. 134) : Derangement of the v.igus nerve is the main source of the distress which follows ; its sentient branches are blunted, and the lungs no longer invite a flow of blood ; its motor branches con- vey only cramp to the muscular parts ; the mechanical suction-power of the chest is depressed, and the lungs themselves tend to collapse. The right heart soon becomes distended ; cardiac distress is complained of; the pulse loses force and volume, in- termits, and syncope results. '