Page:The Harveian Oration,1902.djvu/19

 not obscurely foreshadowed the distinction between the splanchnic and somatic systems of nerves rendered more precise in recent years.

Harvey knew that the heart of a cold-blooded animal would continue to beat when removed from the body, and even when cut to pieces, each portion continuing to execute its own rhythmical contractions. Though he does not specially discuss the cause of the heart-beat, yet one may gather from many passages in his writings, that he considered the heart to be endowed with an inherent activity of its own, independently of the brain and nervous system. The discovery, in more modern times, of the ganglia in the substance of the heart by Remak, Bidder and Ludwig, naturally led to the belief that its contractions are conditioned by rhythmical stimuli, proceeding from these intracardiac centres, just as the somatic muscles are normally excited to action by stimuli conveyed from the brain and spinal cord. Though, perhaps, the last word has not been said on this much-debated question, the balance of evidence, largely furnished by the ingenious and skilfully devised experiments of Gaskell, is in favour of the view that the