Ncrvou? Influence Dr. Brown- 



17 



tivlty although it consists ITJ stopping a movement. It 

 is just as if you were to stop the wheel of a carriage by 

 pushing a wetl-o under it forcibly. 



ACTION OF THE NICKVOU8 SVSTEM ON THE IIEAUT. 



Tlio great agents or tlio rhyi iimtral movement of the 

 heart are small ganglia, composed of c, '11s of gray mat- 

 ter. They arc suddenly rendered iassivo by Hi' 1 

 1'iTiiliar influence exerted upon them. Such an e fleet 

 bus been observed, first, by tlio g.ilv miz uion or the 

 nerve of tlio neck that I spoko of; and it was afterward 

 found to appear when tlio medulla ob'ougata, or center 

 from which that nerve Starrs, was galvanized. i u cx- 

 p?riments made by a French physiologist Leg.allois it 

 was found that the crushing of tlio medulla oblongata 

 produced an arrest of tlio heart. But lie did not dis- 

 criminate between that kind of cessation and death. 

 He thought that death was caused by this crushing of 

 The minimi:. oblongata, and that the heart had ceased 

 because it Had lost the source of its action. "When I 

 took up the question I found that a f-imule pricking of 

 the medulla oblongata could produce au arrest of the 

 heart's action. My friend. Prof. Charles Runlet, who 

 took up the question of the mechanism of the phenomena 

 by which an organ is arrested in its activity, considered 

 that what takes place iu the he.irt is similar to other 

 phenomena which he noted at the time he published 

 his paper. Ho established this law : that all suoii 

 phenomena which I shall call tho phenomena of arrest, 

 though in English they are generally called inhibitory 

 phenomena occurred always through the same 

 mechanism. An irritation starts from a pare which can 

 convey rervous force, and the nervous force so con- 

 veyed after that irritation, reaches the cells of gray 

 matter which were active, and those cells of gray mat- 

 ter are immediately stopped by that peculiar influence. 



For another illustration of this uiecnanism we are in- 

 debted to the observation of a very intelligent negro, 

 whoso master was affjcted with a disease of the spinal 

 cord which produced convulsions iu the lower limbs. 

 The most intense stiffness would manifest itself in the 

 lower limbs. They were rigid like a bar of iron for a 

 time; and alter ten minutes of this extreme rigidity 

 they began to have violent. jerks. The jerks then disap- 

 peared aiid the rigidity returned. All :tay long ihe lower 

 limbs were in this state of muscular contraction. His 

 servant, tho negro, having to dress him, found it very 

 difficult to put on his pantaloons. Ouo day, ho by chance 

 took hold of his big toe, and found as he pulled it that 

 the limbs became perfectly soft and movable. 

 The convulsions had disappeared altogether. The 

 neero certainly had a natural genius for science. [L ingh- 

 ter.] He learned the meaning of tho fact. Pie learned 

 that whenever ho wanted to push his master's panta- 

 loons up, he had only to pull his big too down. [L-ingh- 

 ter and applause.] He succeeded every lime. And as 

 the master found the cessation of the convulsions useful 

 at other times besides when he was dressing, the negro 

 was asked very frequently to act on the big toe in order 

 to effect it. [Li lighter.] Tuis fact is not a unique one. 

 I have seen 14 such cases. Many of my medical triends 

 tave s.;eu them also. In fact it seems somewhat a rulo 

 In cases where there is a certain disease of the spinal 

 cord limited to a certain part, that this will be found. 

 In this case you find exactly the same thing that exists 

 in the heart when the par vuyiun is galvanized. In both 

 instances there is a nerve that conveys irritation to tho 

 cells. In tho case of the heart the. nerve goes to tho cells 

 that are in the heart. In tho case of the big toe, the 

 serve poes to the cells that were in a morbid state pro- 

 ducing tijoee convulsions. In the one case, that of the 



heart, tho phenomena of movement were nominal ; in 

 tlio other, the phenomena were morbid. Still, it was tho 

 same mechanism in both. In boll; instances a cessation 

 of activity was produced. 



rUEi'SUUE ON THE NECK TO CHECK THE HEART'S ACTION. 



A friend of mine. Dr. Waller, a ino.st intelligent man, 

 a man of genius although lie was not a negro found 

 that by pressing on the neck he could produce tho most 

 interesting ptysiological phenomena. Ho lias succeeded 

 in that way in curing headaches, neuralgia of tho face, 

 and many other affections iu which there was pain or 

 ureat congestion <f tho head. Au attack of epilepsy 

 may be stopped in tlxut way. Many physicians before 

 him had produced eoPie of those results, but they all 

 thought it was from % pressure of tho carotid artery. 

 Dr. Waller has tho merit of showing that it is ehielly 

 he thought it was only, but I have found that it is chiefly, 

 not only through an irritation of that nerve, the par 

 raijuni, that the motion of the lieart is arrested In thoso 

 cases, and that a diminution of the beating of tha hearo 

 was followed by an amelioration in the circulation in 

 tho head, a cessation of an attack of epilepsy and of 

 various other complaints. It wai something, therefore, 

 quite different from the mere pressure ou the carotid 

 artery. Taese views wore not absolutely complete, as I 

 have found that another nerve which goes to the blood 

 vessels of tho brain is also irritated by the process ; 

 and that tlio pressure exerted in the neck produces three 

 effects: (I) It certainly diminishes the current in tho 

 carotid artery, and indeed stops that current altogether 

 if tho pressure is considerable ; (2) it diminishes the cir- 

 culation considerably, and may in luce a profound state 

 of syncope by acting ou the par var/ani; and (3) it also 

 acts on the cervical sympathetic, and produces a con- 

 traction of the biood vessels in the head, by means of 

 which a part of the good effect is obtained. 



There are perhaps no parts of the nervous system 

 which cannot under irritation have an influence on 

 the heart to stop it. Even irritation of the nervous 

 fibres of the brain may produce a cessation of the ac- 

 tivity of the heart. Physicians iu this room know per- 

 fectly well that sometimes a patient stricken down with 

 apoplexy may have a great reduction iu the action of 

 the heart, and sometimes syncope may take place, re- 

 sulting in death. In tho spinal cord it is so also. There 

 are indeed parts that cannot bj prickel by the tiuest 

 needle without some influence on tho hoirt. Legallois, 

 the French physiologist, of whom I have already spoken 

 thought that all of the spinal cord was a center for the 

 movements of the heart, and he had made experiments 

 which seemed certainly to show that that was the case. 

 He had passed a Sii'ill bar of iroa along a par; of the 

 spinal cord, and liad found that that stopped the heart's 

 action. But he made a mistake in considering that it 

 was because ho had destroyed the nerve center of the 

 heart. 



GREATER VITALITY IN AMERICA THAN IN EUROPE. 



This experiment was the occasion, as perhaps some of 

 you already know, of my finding tiiao animals in this 

 country can bear an injury far more easily than tho 

 same animals iu Europe. I have ascertained that it is 

 so for man also. And this is why so many medical 

 writers iu Europe consider that facts of this kind pub- 

 lished here are mere inventions. Tnero is a distrust 

 among European physicians in tlio honesty and up* 

 rightucss of American physicians, because tho former 

 cannot understand how man in this country can sur- 

 vive terrible injuries which would bo fatal to him in 

 Europe. I would not say that the truth is absolutely 

 respected in this couuiry or anywhere else, but still 



