"Moreover, if an egg be exposed too long to a colder atmosphere, its leaping point pulsates less often and stirs more languidly; but if a warm finger be applied to it, or any other bland source of warmth, straightway it recovers strength and vigor. Indeed, when such a point has become gradually weak and though full of blood ceases to move at all and gives no sign of life, seeming utterly to have succumbed to death, if my lukewarm finger be placed over it for the space of twenty pulsations of my artery, behold! the little heart revives once more, becomes erect, and renews its pristine dance as though come back from Hades. This I myself and others, too, have brought about again and again by means of gentle warmth of any kind, such as that of a fire or of tepid water; thus at our pleasure being able to give over the poor little soul to death, or call it back to the light."[201] As in the embryo the leaping point may be revived by external warmth, so may the heart in the full-grown bird. In his treatise of 1628 Harvey says:-- "In the pigeon, at any rate, at an actual experiment, after the heart had wholly ceased to move and even the auricles had left off moving, I placed my finger, wetted with saliva and warm, upon the heart and kept it there for a while; as the result of which fomentation the heart, as though restored to strength and life again, and its auricles with it, were seen to move and contract and relax themselves and, as it were, to be recalled from death."[202] In his treatise On Generation, Harvey confirms the doctrine of the primacy of the blood by citing observations made upon sluggish or hibernating animals and also certain morbid phenomena in man, as follows:-- "This, too, clearly follows from many observations; especially the cases of certain animals which possess blood yet live a long time without a pulse; and of some which lie hidden the whole winter and, nevertheless, continue alive, although meanwhile all movement of the heart has ceased and their lungs enjoy a rest from breathing, like people who lie half dead and pulseless in syncope or faintness or hysterical affections."[203]