Forwards it covers, and has driven asunder, the optic lobes; backwards it hides the much shortened medulla oblongata.
The action of aconitine on the circulation is due to an initial stimulation of the cardio-inhibitory centre in the medulla oblongata (at the root of the vagus nerves), and later to a directly toxic influence on the nerve-ganglia and muscular fibres of the heart itself.
The final arrest is due to paralysis of the respiratory centre in the medulla oblongata, hastened by a quasi-asthmatic contraction of the non-striped muscular tissue in the bronchial tubes, and by a "water-logging" of the lungs due to an increase in the amount of bronchial secretion.
Consciousness is entirely unaffected by physostigmine, there being apparently no action on any part of the brain above the medulla oblongata.
The cerebral convolutions remain unaffected, but the important centres of the medulla oblongata are stimulated.
