Chap, xiii.] CIECDLATION. 205 



there is in the embryon the smallest trace of nervous system, 

 and at a later period, in the adult, when the motory nervous 

 system is killed by the help of the poison curard, the heart 

 continues nevertheless to palpitate. It is even totally freed 

 from dependence on the nervous centres, and we no longer 

 succeed, as in the heart's normal state, in suspending the 

 cardiacal beatings by irritating one of the principal sources 

 of the heart, the pneumogastric nerve.'' 



In efEect, in the state of integrity of the organism, the 

 heart, spite of its independence, is bound by its nervous system 

 to the rest of the organism, and specially to the brain. The 

 rapid ingestion of a very cold drink into the stomach provokes 

 a contraction of the vessels of the brain, thence ansemia of 

 that organ, and sometimes stoppage of the beatings of the 

 heart, whence death can result.^ A sudden stoppage of the 

 beatings of the heart can also be provoked by a shock on the 

 epigastrium : it is produced when the heart and the viscera of 

 a frog, being laid bare, we strike a violent blow on the abdom^inal 

 viscera.^ A sharp pain on the passage of a sensitive nerve 

 . produces the same efiect.* If we electrise any nerve whatever 

 the heart stops in its state of dilatation, in diastole. The 

 result is the same in a frog, if we electrise the origin of the 

 spinal man'ow, the medulla oblongata.^ But the stoppage of 

 the heart in diastole is produced more surely still if we electrise 

 the nerves which connect it direct with the brain, the pneumo- 

 gastric nerves. 



Moral impressions produce the same efEect. Syncope fre- 

 quently follows a strong emotion. This is a fact of common 

 observation. Sometimes, on the contrary, emotions provoke a 



1 Saissy, Eegnault. — See also Gavarret, Des Phinomines Physiques de la 

 Vie, p. 227. 



' E. Ganz, Ucher die Gefahr des Tcallen Trunkes bei erhitziem Korper 

 {Pfliiger's ArcMv, 1870). 



* Brown-S^guard, Arehmes G^nirales de Midiciiie, 18S6, t. VIII. 



* CI. Bernard, Sur la Physiologic dw Coeur. 



^ Vulpian, Lefons sur la, Physiologie du Systime Nerveux, p. 853. 



