Page:The Harveian Oration,1902.djvu/60

 are only mediately produced through the respiratory centre, which we know is to a considerable extent governed from the cerebrum. The cardiac and vascular centres in the proper sense of the term are in the medulla oblongata and the hemispheres are to them as much peripheral as the sensory nerves in general. The same may perhaps be affirmed of the so-called centres of the salivary and digestive glands recently described by Bechterew and his pupils.

Through what centrifugal channels the cerebral hemispheres influence the cardiac and vaso-motor centres is not definitely ascertained, but they probably traverse the tegmentum beneath the corpora quadrigemina. For in this region electric stimulation, as Danilewsky, Lauder Brunton, myself, and others have shown, invariably produces such alterations of cardiac and respiratory rhythm and vascular tone as might well be regarded as signs of irritation of the paths by which the cortical centres transmit their influence to those of the