CAUSES OF rALPITATION. 421 



and hard, and it was firmly attached to the trachea. The eyes 

 were sunken, but not greatly. 



The cause of death here has evidently been oedema of tho 

 Jungs, which has come on rapidly and insidiously. 



In tills case, the three prominent symptoms of exophthalmic 

 goitre, although present, are not so noticeable as in many others ; 

 but the collateral symptoms, such as the imperfect consensus 

 between the movements of the upper eyelid and visual plane, 

 oil which Von Griife laid particular stress, the emotional cha- 

 i^acter. the feelings of heat, the actual high temperature noticed 

 by Teissier, are particularly well marked. To trace the 

 ■symptoms back to their origin is exceedingly difficult, and, 

 indeed, impossible, in the present state of physiological know- 

 ledge. All that we can hope to do at present is to put together 

 the facts already ascertained, so that we may gain a clearer 

 idea of the possible origin of the symptoms, and see more 

 readily what points remain for investigation. 



Palpitation. — Three causes of palpitation at once suggest 

 themselves to the mind, and these three are undoubtedly the 

 -chief, although there may be, and probably are, others which 

 occasionally come into play. These three are — 1. Paralysis of 

 the vagus ; 2. Eelaxation of the arterioles ; 3. Stimulation of the 

 accelerating nerves of the heart. The vagus acts as the regu- 

 lating nerve of the heart, not only by diminishing the number 

 of its pulsations, but by moderating their strength. Paralysis 

 of this nerve, therelbre, causes palpitation of the heart, as well 

 as quickness of the pulse. Palpitation depending on this cause 

 may be compared to the excessive work done by a steam-engine 

 from which the governor-balls have been removed. l>ut a 

 •steam-engine may also work with excessive and injurious 

 violence if tlie resistance it has to overcome is much diminished, 

 •especially if this occur suddenly, and the governor-balls, 

 although present, work imperfectly. The same is the case with 

 the heart, which is very liable to palpitate violently when tho 

 arterioles become relaxed from weakness of the vaso-motor 

 system, and allow the blood to pour readily through tliem into 

 the veins, instead of opposing a moderate amount of resistance 

 to its passage. 



