During the course of a consideration of the occurrence of respiratory arrhythmia in old age, it became evident that there was an increase in certain vagal effects, coincident with increased age.
That there is such an increase in vagal activity, is not a new observation. Mention of such an increased activity has been made from time to time, but little definite evidence is to be gained from the literature.
Allbutt1 predicates such an overaction of the vagus with age. He cites Dr. Hugh Anderson's experiments showing an increased vagus action in old cats and not in young kittens. He also quotes Wenckebach's observation that he had found the vagus especially active in anginal cases. More recently Vinnes2 has shown that the effect of pressure over the vagus trunk was more pronounced in adults than in children. Glaser,3 however, by a different method, concludes that the vagus is more active in