It is a familiar fact that the heart of cold-blooded vertebrates may continue to beat for a long period–even for days–after its removal from the body, but it is not so well known that contractions may occur in the heart of the higher vertebrates for a considerable time after death. On this latter point, however, there are many observations on record. Harvey noted that rhythmical contractions continued in the heart of the pigeon for some time after death, and, further, that after it had ceased to beat, it recovered its vigour, and both auricles and ventricles pulsated on the application of a stimulus, such as the tip of the finger wetted with saliva.